Blue Scarab 
Enchantment — Aura
Enchant creature Enchanted creature can't be blocked by blue creatures. Enchanted creature gets +2/+2 as long as an opponent controls a blue permanent.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL