Card sounds may differ from in-game as they get updated.
Killer - A unit with Killer can make one special attack directly against an enemy unit. This can be done the turn it's played, and can target any unit, regardless of Flying, Aegis, or other special abilities.
Summon - Does something when played
Spellcraft - When you play a weapon with Spellcraft, you may spend power to create and play the listed spell.