Siege Rhino

The six-point life swing is the entire pitch, and it is what makes a four-mana 4/5 a problem the opponent has to solve rather than ignore. The body alone is a fair midrange creature: hard to kill in combat, awkward to chump because of trample, large enough to threaten a clock. The enter-the-battlefield drain is what converts that fairness into pressure. Trade it in combat, block it down, or remove it before it swings, and you have already taken three to the face and watched your opponent gain three; the card has done its job before it ever attacks. That made it the standard-bearer for a generation of grindy three-color midrange decks, the creature that taught a format how punishing it was to be on the back foot against a deck that gained life and pressured your total in the same spell. It is also a clean lesson in how to push a four-mana creature without making it broken: the three colors of pips are the cost of the rate, demanding a manabase that can support white, black, and green by the fourth turn. Everything good about it is front-loaded into a one-time trigger, so the answer is never to outvalue it later but to have already paid the tax of letting it resolve. Few four-drops have ever defined what "value creature" means as precisely.