Piranha was the name of a terrible hack of Pac-man. It was released in 1981 by "GL" as it is quoted on the attact mode screen. You played a piranha trying to eat all of the dots in a free-form area (no walls to speak of), with the ghosts replaced by Octopi or some sort of squid monster. The graphics and sound are terrible, and the play control is awful. The ghost logic seems to still be used to having walls, so they make some poor decisions when trying to hunt you down. All in all, not a very good hack.

An insane rarity (if it even still exists) in arcades, this hack is playable in MAME with the standard pacman driver.