Changeling Berserker

Champion was the keyword that charged you twice for the same aggression: cast the creature, then strip another body off your board or watch this fall to its own enters trigger. A 5/3 with haste wants to swing the turn it lands, but the entry clause forces you to exile something already in play to keep it around. What sets this apart from the tribal champions of its era is the wording of the keyword: most demand a specific type (champion a Goblin, champion an Elf), while this one simply reads "Champion a creature," so any of your bodies qualifies. The Shapeshifter typing closes the loop from the other side, since a creature wearing every tribal label can be championed by whatever tribal Champion you cast afterward. That turns the keyword from a deckbuilding lock into a portable value chain: champion a fragile attacker to shield it from a sweeper, swing for a meaningful chunk, and recur the exiled creature with a fresh enters trigger the moment this leaves. The trade is real, not cosmetic: you collapse your board to one fast threat, betting the saved creature plus the returned trigger outvalues the spent one. The two triggers function like Oblivion Ring's, so answering the Berserker in response to its enters trigger actually protects you: the leaves trigger finds nothing exiled, and you decline to exile when the enters trigger resolves. A blunt instrument welded to one of the fiddliest mechanics of its time.