Groffskithur

The joke is the recursion clause, and the joke only works because the card refers to itself by name. Get one Groffskithur blocked and you fetch another Groffskithur back to hand, which you can cast and get blocked and fetch the first one back, an infinite loop of beasts trading combat steps for graveyard trips. It is a designed pun on the redundancy templating Magic uses for tokens and cycles, repurposed so a vanilla-ish 3/3 can reassemble itself out of the bin again and again. The catch that keeps it from doing anything: it triggers on being blocked, not on dealing damage or dying, so all the loop actually buys you is card advantage that requires a willing opponent and a board state that already has your beast pinned in combat. There is no payoff attached, no death trigger to feed, no token to spawn, no counter to grow. The recursion is the whole gag and the gag terminates in your hand. As a piece of artifact-set humor it is memorable precisely for how little it accomplishes: a creature engineered to come back forever, given nothing worth coming back for.