Lazboll, Butterfly Shaman

At the beginning of your upkeep, exile the top 5
cards of target opponent's library. You may play
cards revealed this way and you may spend mana
as though it were mana of any type to cast those
spells.
At the beginning of your end step, return all
remaining cards exiled by Lazboll to the bottom
of their owner's library in a random order.