Curio Snail

{1}{w}: Whenever target creature deals damage this turn, its controller gains that much life.
{1}{u}: Whenever target creature attacks this turn, untap target permanent.
{4}{b}{b}: Change the text on each permanent by replacing each instance of "destroy" with "regenerate", "gain" with "lose", "tap" with "untap", "attack" with "block", "scry" with "fateseal" and vice versa