Creatures can't attack you or planeswalkers you control unless their controller pays {X} for each of those creatures, where X is the number of enchantments you control.
Mana cost
4
W
Mana value
5
Printings
From
$3.46
EDHREC rank
#671
Buy
Formats
Pioneer
Legal
Modern
Legal
Legacy
Legal
Vintage
Legal
Commander
Legal
Rulings
1 Oct 2012
If you control Sphere of Safety, your opponents can choose not to attack with a creature with an ability that says it attacks if able.