Text (4th/5th/6th/7th/8th/10/CF/M10+errata): Return target creature to its owner's hand. [Oracle 2009/07/08]
Unsummon can be used during combat in the steps after attackers or blockers are declared to remove an attacker or blocker so that creature does not deal damage. [D'Angelo 1994/10/01]
Unsummon can be used during combat after combat damage is assigned but before combat damage resolves. If this happens, the creature does not receive damage, but the damage it assigned will still become dealt. [D'Angelo 1999/05/01]
If this causes an opponent to go over 7 cards when it is not their turn they need not discard until the discard phase of their next turn. [D'Angelo 1994/06/01]
Unsummoning a token creature removes it from the game. [bethmo 1994/10/01] See Rule 110.5.3.
