Oko, the Trapped

0: Oko, the Trapped can't activate loyalty abilities unless there is another Planeswalker on the battlefield. Planeswalkers cost {1} less to cast
+1: Oko becomes a nonlegendary copy of target permanent and may use an additional loyalty ability until end of turn. He retains his loyalty abilities
+1: Target permanent becomes a non-legendary copy of Oko, the Trapped(And whatever he is copying). Only one Oko can use this ability per turn.