Kaseto, Orochi Archmage
Oracle Text
: Target creature can't be blocked this turn. If that creature is a Snake, it gets +2/+2 until end of turn.
Card Rulings
11/4/2015 Once a creature has been legally blocked, activating Kaseto’s ability targeting that creature won’t cause it to become unblocked. It will give it +2/+2 if it’s a Snake, though.
Not to mention that his/her effect targets ANY creature, not just yours. Political card for sure.