Pictures on Google’s mapping tool show what could be the massive insect scuttling on an island off the coast of Mexico.
The discovery has prompted fears that the J’Ba Fofi – also known as the Congolese Giant Spider – has spread to central America.
The mysterious breed is said to exist in the Congo is alleged to be as large as a monkey.
“At this size it would devour an entire person to satisfy its hunger”Scott C Waring
But it has only been seen a handful of times since the 1930s.
Not everyone is certain it's a spider, however.
One Brit commented: "The J'ba Fofi has returned, but this time in Mexico.
"First the Congo then the Amazon, Louisianna US, Peru, New Guinea now Mexico. They're slowly starting to spread. Be aware and careful."
Renowned UFO hunter Scott C Waring posted the picture to his popular UFO Sightings Daily website and claimed it was a monster crab.
He wrote: ”The crab itself looks enormous, about the size of a bus - using the road as measurement at the end of the video.
"This is an awesome discovery and just goes to prove that scientist don't have the slightest clues about the hidden giant species that exist in the oceans of the world.
"At this size it would devour an entire person to satisfy its hunger...so watch out for this giant spider when you are on your next fishing trip, and be aware, you may be the next catch."
The Japanese Spider Crab currently holds the record for largest crustacean – boasting a 4m leg span.
But as the name suggests, these are typically found off the southern coast of Honshu, Japan.
Several have called time on the chilling picture, however.
Many claimed the discovery was a hoax after YouTuber MexicoGreek refused to publish the coordinates after uploading it to the web.
The picture has little depth and shadow, and as one YouTube commenter pointed out: "No coordinates…hoax…People like you love clickbait."
It comes as several have posted pictures of spiders bursting from eggs in unsavoury places.