Planeswalkers all have one or more loyalty ability, and they can use one on your turn to gain some effect, usually building up or depleting their loyalty in the process
Umaro, Raging Yeti* Straight to you from the World of Ruin in the Revival Trance Commander Deck, Umaro is a beast of a design as a 6/6 for 6 with trample who will either pump your board, shoot something, or wheel you each turn at random
They are all good quality cards, they might even plug a good hole in your deck but they are very much off theme cards
The effect is powerful, but often awkward too, since sometimes you end up bouncing more of your stuff than your opponent's
Most importantly, they tend to have a habit of saying "Kupo!" loudly, a term you may have heard in nerd spaces over the years
If youre feeling risky, Phyrexian Purge can be used to your advantage with the higher life totals in Commander