Guy, the Twelve-Sided

At the beginning of your upkeep, if Guy has fewer
than twelve face counters on it, you may exile target creature and put a face counter on Guy.

{2}{g}{u}: Guy becomes a copy of target creature
exiled with Guy, except its name is Guy, the
Twelve-Sided, it's a legendary green and blue Shapeshifter, and it has all abilities of this creature
in addition to its other colors, types, and abilities.