I couldn't miss the chance to practice my drawing!
The dancing Tifa glitch is a glitch in Final Fantasy VII where the game crashes during the scene where the party is inside Bugenhagen's planetarium. It is not known what makes the glitch trigger, and whether it only happens in certain versions of the game. The glitch is generally said to occur when Cloud is in the middle-position of the party and Tifa is on the bottom-position as displayed on the menu.
If the glitch activates when Bugenhagen is explaining the Planet and the Lifestream, the game will freeze except for Tifa. The player can control her and she is given the same movements used when she is trying to escape the gas chamber later on in the game, making it appear like she is dancing. This may be fixable by restarting the game, or the player will never be able to get past it, ruining their save. It may also be possible for the "dancing" glitch to happen to characters other than Tifa.