Text (WL+errata): Whenever a creature you control attacks, it phases out at end of combat. [Oracle 1999/07/01]
Remember that if there is more than one thing scheduled for the end of combat to use the "active/current player's abilities first in any order they choose, then the other player's abilities in any order they choose" rule for placing the abilities on the stack. For example if a Fog Elemental attacks and you control a Teferi's Veil, you get to choose which of the "phase out" or "bury" effects happens first (and the other one fails to happen). [D'Angelo 1999/07/10]
