At the beginning of your upkeep, you may have this creature become a copy of another target creature, except it has this ability.
"If left in the enemy's shape too long, it might be lost to them."
—Vy Covalt, Neurok agent
(01/06/2011)
If another creature becomes a copy of Cryptoplasm, it will become a copy of whatever Cryptoplasm is currently copying (if anything), plus it will have Cryptoplasm’s triggered ability.
(01/06/2011)
If the creature is an illegal target when the ability tries to resolve, it won’t resolve. Cryptoplasm won’t become a copy of that creature; it remains whatever it was before.
(01/06/2011)
The copy effect lasts indefinitely. Often, it will last until it is overwritten by another copy effect (if it copies another creature on a future turn, perhaps.)
(01/06/2011)
You choose the target for the triggered ability when the ability is put onto the stack. You choose whether or not Cryptoplasm becomes a copy of that creature when the ability resolves.