Uriaris, Fel Survivor

When Uriaris, Fel Survivor enters the battlefield, create Samaster, a legendary 3/3 black Spirit Dog creature token with menace.
When a creature token you control dies, you may pay {3}. If you do, regenerate that creature.
When a nontoken creature you control dies, you may pay {w}{b}{1}. If you do, regenerate that creature.