Wandering Mystic

Hexproof
{2}{t}: Wandering Mystic deals 1 damage to target creature. If that creature dies this way, its
controler makes Wandering Mystic deals X
damage to another target creature, where X is
equal to the last damage done in this way plus 1.
If that creature dies this way, repeat this process.
{t}: Add {r} or {g}.