Rightful Companion

When Rightful Companion enters the battlefield,
it deals X damage to any target you don't control.
Where X is equal to the number of nonartifact creatures you control.
Sacrifice Rightful Companion: Target creature
you control gets +1/+0 and gains indestructible
until end of turn.
"Who's a good stone.. dog.. thing..."
—Cair, Battle Armorer