The invisibility glitch is a harmless glitch in Dissidia Final Fantasy. The glitch happens when a player triggers an action that coincides with a Chaos or Cosmos Judgment rule coming into effect. The player action will occur as normal, but depending on the situation neither one or both of the characters nor the attack animation will be seen. This glitch has been shown to occur with both regular attacks and EX Bursts.
Another variation of this same glitch keeps characters visible, but instead the camera is far away so the characters appear as though they've been inflicted with the Mini status.