Quikken, Rebirth of Memories

Slow-start (This creature enters the battlefield tapped.)
Vigilance, deathtouch
When a creature you control dies, you may exile it with a memory counter on it. Activate this ability only once each turn.
Once per turn, you may cast a copy of a creature exiled with a memory counter on it for {x}{w}{r}{g}, where {x} is equal to the number of memory counters on it. It's a sand in addition to its other types. If you cast a copy of target exiled creature this way, put a memory counter on it.