Guardian Beast 
Creature — Beast
As long as this creature is untapped, noncreature artifacts you control can't be enchanted, they have indestructible, and other players can't gain control of them. This effect doesn't remove Auras already attached to those artifacts.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL