Sifter of Skills

Whenever a creature enters the battlefield under your control, you may choose two of the following: first strike, flying, deathtouch, haste, hexproof, lifelink, menace, reach, skulk, trample and vigilance. If you do, that creature loses the first ability and, if an ability was lost this way, gains the second ability.
"Now listen closely boys. When they're on guard, we sneak around them and when they're off guard, that's when we charge in screaming blue murder."