Final Fantasy VI
Bugs

Relm's Sketch Bug
This bug is now pretty famous (infamous?). It involves Relm (or Gogo) sketching a monster and then the bug occurs. It seems to happen most when sketching large enemies, unusual enemies, or invisible enemies (Gau, Intangir, etc.), but can occur when sketching normal monsters. The bug may do a number of different things, it may:
1. Reset EVERYTHING (i.e. three empty save slots)
2. Permanently mess up saved games
3. Give your party tons (as many as 255 [it'll say 0]) of different items. Anything from Dirks to Economizers and Gem Boxes.
4. Just freeze up (meaning you'll have to reset)
5. Erase items from your inventory. It may have been fixed in later versions of the game.
About the only way to make sure you don't encounter this bug is to simply not sketch.


Duncan Bug
If you go to Duncan's house in the World of Ruin before getting Bum Rush and without Sabin, you'll find Duncan practicing in the house. Press 'X' to go to the subscreen then 'B' to return. Each time you do this Duncan will restart his jump. By doing this over and over you can make Duncan jump through the wall and into the black space around the room.