Optimus Prime, Hero

More Than Meets the Eye 2URW (You may cast this card converted for 2URW.)

At the beginning of each end step, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

When Optimus Prime dies, return it to the battlefield converted under its owner's control.
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Optimus Prime, Autobot Leader

Living metal (As long as it's your turn, this Vehicle is also a creature.)

Trample

Whenever you attack, bolster 2. The chosen creature gains trample until end of turn. When that creature deals combat damage to a player this turn, convert Optimus Prime.