Hall of Shapeshifters

At the beginning of your end step, target blue or
face down creature you control gains "At the beginning of your upkeep, you may have this
creature become a copy of any creature on the battlefield, except it doesn't copy that creature's
color or creature type, and it has this ability"
and the creature type Shapeshifter.
{1}{u}: Shapeshifters gets +1/-1 or -1/+1 until
end of turn.