Mystlyf, River Styx Guide

Bestow {1}{u}{b}
Mystlyf has hexproof and cannot be blocked
Enchanted creature gets +1/+1, has hexproof,
and cannot be blocked.
Whenever Mystlyf or enchanted creature deals
combat damage to a player, put a copy of
Mystlyf onto the battlefield that's not legendary.
If it's an Aura, you may choose a new target
for the copy.