When Rainbow Knights enter the battlefield, it gains
protection from a random color
(A permanent or player with protection can't be targeted, enchanted, equipped, fortified, damaged or blocked by sources of the given property.).
: Rainbow Knights gains
first strike (This creature deals combat damage before creatures without first strike.) until end of turn.
: Rainbow Knights gets +0/+0, +1/+0, or +2/+0 until end of turn, chosen at random.