Colossal Skyturtle

Discard it and you get a Regrowth or an Unsummon; hard-cast it and you get a flying 6/5 with ward. The seven-mana body is deliberately overpriced, because the card was never designed to be a seven-drop first: it is built to be two efficient spells that happen to share a card, with an expensive finisher as the fallback for the rare game where you flood on land and want a threat. The two channel modes are the point. For you pitch it to return any card from your graveyard; for you pitch it to bounce a creature to its owner's hand. The discard cost is what makes the whole thing pay for itself: a fatty you would almost never commit six-plus mana to becomes fuel for value or tempo, and the graveyard becomes the delivery point for effects that normally cost a full card each. What you buy is the guarantee that the card is never a blank: it can be a threat when the game goes long, a recursion spell when your graveyard has something worth digging up, or an interaction spell when a creature needs to leave the board. The cost of that flexibility is a beat of efficiency on every mode, and a 6/5 that is fragile for what hard-casting it demands. This is the modal-flexibility archetype pushed toward its limit, a single slot that refuses to be dead in any half of the game.