Kaseto, Orochi Archmage 
Legendary Creature — Snake Wizard
: Target creature can't be blocked this turn. If that creature is a Snake, it gets +2/+2 until end of turn.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL