Silly Doppelganger

Upon summoning, Doppelganger acquires all characteristics except color of any one creature
in play on either side; any creature enchantments on
the original creature are not copied. During
controller’s upkeep, Doppelganger may take on the characteristics of a different creature in play instead. Doppelganger may continue to copy a creature even
after that creature leaves play,
but if it switches it won’t be able to switch back.