The monster from Goonies was called Sloth, who was actually the deformed youngest brother of the Fratelli crime family.
In the movie, The Goonies, Chunk is captured by the Fratellis after the the group of kids find — and follow — a tunnel leading into the earth. The bad guys lock up Chunk with Sloth, who eventually befriends the chubby youngster and helps them both escape … and go to police.
Former Oakland Raiders defensive end John Matuszak played the role of Sloth.