Sphere of Safety 
Enchantment
Creatures can't attack you or planeswalkers you control unless their controller pays 
for each of those creatures, where X is the number of enchantments you control.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL