Carlos Mercado and “The Doctor”

First Published: February 2, 2018 Last updated: February 8th, 2019 Written by: Marcus Lowth Estimated Reading Time: 6 minutes Posted in: Aliens

UFO Investigator, Bob Pratt, would state about the uniqueness of Puerto Rico, was that in this part of the world “UFO cases are occurring everywhere all the time!”

Furthermore, Pratt would claim that the area had many sightings of “UFOs entering or leaving the sea”, as well as “entering mountains” and even landing. It would appear that the sightings are so varied and constant, that the area is some kind of gateway or outpost.

UFO Mountain

We recently looked at the account of Orlando Jorge Ferraudi, who made claims of an underwater alien base in the Gulf Of Mexico. Relatively speaking, this is only a stone’s throw away from the apparent UFO surges around Puerto Rico.

We have also looked several times at other claims of alien bases underwater or in mountains. All have similar details and assertions. The story of Carlos Mercado, who would speak to Pratt in December 1988 six months after his encounter, would appear to confirm these assertions.

July 1988, Puerto Rico

Despite the late hour, it was still stiflingly hot in Carlos Mercado’s home. So much so, that he left his bed he shared with his wife and went out to the couch in the sitting room. It did appear to be cooler in the next room, but not much.

Before he could completely settle into sleep, however, a humming noise began to ring in his ears. It was getting louder, and seemingly, closer.  A glow began to push through the window from outside. He sat up, nervous and unsure what to do. When the tap at the window came, he jumped a little.

Slowly, he moved to the window and peered out. Looking back at him were three small humanoid figures. They had large, dark eyes, and much larger heads for their bodies, which were tiny and frail by comparison. They stood around three to four feet in height and each adorned grey-cream overalls “like mechanics wear!”

Before he could comprehend anything else, a voice “appeared” in his mind asking him to come outside. It must have belonged to one of the creatures, but he saw nothing to indicate they had physically spoken.

He looked past the three figures and saw a large, shiny saucer-type craft waiting behind them. He calmly opened the door and followed them. They were now walking towards the gleaming, silver object.

Inside The Saucer

As he walked the voice continued, saying not to be afraid and they were not here to hurt him. As the voice spoke, any fear that was still inside left him.

By the time he reached the craft, he was right at the side of Highway 101. He could now see an array of lights on the underside of the object, and definite windows (of some sort) on the upper, raised cupola. It stood on a set of legs that came out from the base of the craft, and a set of ladders protruded from an open middle section. Interestingly, this description matches many other such reports of close contact, lending the account further credibility.

The creatures motioned for him to climb the ladder to enter the craft. He did so. Upon climbing into what seemed to be the control room, he could make out different “panels, controls, and little lights!” There were also other creatures like the three that had come for him, all busy at their apparent stations.

In the middle of the room was another figure, only this one was drastically different.

Alien Focus

The Doctor

The being who had spoken to him inside his head introduced Mercado to this strange, different humanoid. He was, the captain, or “The Doctor!”

The Doctor was much bigger than the others, almost the same height as Mercado himself. His head was still slightly larger than his frame said it should be, but his eyes were not as out of proportion. Unlike the smaller creatures, The Doctor had a nose, similar to a human nose but with a “definite point!”

Around his frame, The Doctor was covered from his feet to his neck, and right down to his hands, in a white tunic. Although he couldn’t see clearly, Mercado believed he could make out some kind of white footwear.

According to The Doctor, Mercado had been brought here so that he could share “something important” with him. And so that he could later tell others.

As he was contemplating this mind-blowing situation, the humming sound returned. Metallic noises also filled the air, and Mercado could feel activity below him. He guessed the legs were retreating, and a moment later, he could feel an anticipation of lift-off. A second or two later, they took off at great speed.

Alien Base “Inside” The Puerto Rican Mountain Ranges

Mercado managed to look out of the window in the control room. Expecting to see the void of outer space, he was a little disappointed when he was greeted with a view of the Sierra Bermeja – a mountain range he was very familiar with.

The Doctor informed him they were heading for a deep ravine. As the craft dived, Mercado began to pull back from the window, fearing they were going to crash into the mountainside. To his amazement “the side of the mountain opened up” and the craft went inside and progressed down a deep tunnel.

Suddenly the craft came out of the tunnel and was in a huge open area. Mercado looked around, scanning his surroundings. They were inside what seemed to be a “huge, gigantic cave” with waves of activity going on.

Their craft would land in a flat section, dominated by other similar crafts, as well as many drastically different ones.  Mercado would later state, there were crafts of all shapes – round, square, triangular, and shapes he couldn’t quite describe. All were unknown to him though.

The Doctor asked Mercado to follow him, and join him outside the craft. As he did so, he was given a pair of huge dark glasses so that he could see everything clearly.

The Base – A Huge Metal-Plated Cavern

As he ventured outside the craft and into the huge cavern-like base, he noticed how bright the whole area was. He could not see where the illumination came from – it was just there. This, interestingly or not, is an often repeated claim made in such close contact cases. So much so, it suggests a very definite method of lighting or energy use that is completely unknown to us.

As he scanned the huge behemoth-like walls, he could see they were covered in what looked to be shiny, metal plates. The whole base was swarming with the small creatures, working on crafts, or at workstations.

As he looked down to the “ground” of the base, he could make out buildings, neatly laid out. It made him think of how military barracks might look from the air.

The Doctor’s voice came into his head again, stating they have called this base home for a “long, long time!” Furthermore, they didn’t wish to leave, nor did they wish any hostilities to humans. In fact, they wished Mercado (and others like him) to prepare people and tell them of their desire to “inter-relate” with humans, openly.

They were approaching people such as Mercado with this request as “The (human) authorities don’t want this to happen!” Further still, The Doctor assured him, those “who possess understanding” will know he is telling the truth.

UFO Base

Many Similar Reports

After some time of conversation, Mercado went back on board the craft, which left the base the way it entered, via the long tunnel and then out of the side of the ancient mountain range. As the craft left the mountain behind, he could see the landscape rearranging itself. He would state to Pratt, “It was as though a part of the mountain, along with its trees and grass and everything, just lifted up!”

He would arrive back at this home shortly after. Upon opening the door and entering his house, he found his wife still sleeping. He lay down and went to sleep himself.

He awoke the next morning and knew that he had not dreamt the events of the previous evening. What’s more, he told his wife of his adventures, and she believed him without question (as The Doctor said those who understand would?).

What is also interesting about Mercado’s account, is that many others who have had similar close encounters with the “grey” aliens described by Mercado, also report to being taken to this area, and report similar “mountain bases”. Pratt himself. would speak to at least two people (a local women and a member of the Puerto Rican military) who had experienced similar encounters to Mercado.

Might this base explain the huge amount of sightings in this particular region of the world?

The Disappearing Jets Incident, December 1988

By the time Mercado made contact with Bob Pratt, he was witness to another strange event over the skies of Puerto Rico. In fact, it was this encounter that led Pratt to the area in the first place.

On 28th December 1988, multiple witnesses would see a huge triangular UFO in the night sky. It shone brightly against the blackness, and its reflection took over the water below. Two US F14 Military Tomcat Jets entered the airspace shortly after the object’s appearance. However, in front of onlookers, the jets were “captured” by the triangular craft, seemingly in an unseen beam of sorts. They then vanished into thin air.

After witnessing this bizarre incident from his home in nearby Betances, Mercado informed Pratt that he had a previous encounter that he “had to tell” them.

He would claim to want no publicity for his account, but that he knew they were “serious and sensible” investigators into such matters. He hadn’t told anybody else of his encounter (besides his wife) for fear of not being believed despite the fact that the whole area had “experienced very strange things!”

As we touched upon in our look at the Vienna Woods Incident, whether Mercado had more information to pass on or not is unknown. Perhaps he passed it on, privately, to Bob Pratt or other researchers? Or maybe, he still has secrets to divulge.

And what of the two Jets that “vanished”. Again, there are many “unofficial” accounts of fighter jets completely disappearing while engaging a UFO. Was this triangular craft part of the same creatures residing in the Puerto Rican mountains? Or might this be a different race of extra-terrestrials altogether?

Check out the video below. It looks at a typical UFO sighting in this part of the world.



The stories, accounts, and discussion in this article are not always based on proven facts and may go against currently accepted science and common beliefs. The details included in the article are based on the reports and accounts available to us as provided by witnesses and documentation.

By publishing these accounts, UFO Insight does not take responsibility for the integrity of them.  You should read this article with an open mind and come to a conclusion yourself.

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About Marcus Lowth

Marcus Lowth is a writer with a love for UFOs, aliens, and the Ancient Astronaut Theory, to the paranormal, general conspiracies and unsolved mysteries. He has been writing and researching with over 20 years experience. Marcus has been Editor-in-Chief for several years due to his excellent knowledge in these fields. Marcus also regularly appears as an expert on radio talk shows including Troubled Minds and Unexplained Radio discussing these topics.

You can contact Marcus via email.

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