The Pyramid encounter glitch is a bug in Final Fantasy VII, or leftover data that exists in the game's coding. It is somewhat a variation of a Test 0 battle involving the enemy Pyramid, which during normal gameplay is only fought once during the first battle with Reno. The battle can be triggered through a cheat device or through the Debug Room, and occurs regardless of the player's status in the game.
The party fights a Pyramid, named êúô0 (äñ) [sic], in a black background and the messages "ENCOUNT ERROR", "If you found this message", and "then please call staff" show throughout the battle. The pyramid also talks in a manner such as monster "I'm sorry"[sic] or monster "that's too bad"[sic]. Regardless, the battle can be finished and the player will return to their current position of where they are playing at. However, if the player flees from battle, the party is trapped in the northwest part of the world map, covered in water.
The garbled symbols in the enemy name are the katakana characters not being rendered properly in the English version. The names are "Test0" through "Test9", with "Test3" missing.