Fusion Elemental

Eight power and eight toughness for five mana is a rate no monocolored creature gets to touch, and the entire price is paid in the mana symbols: one of each color, no shortcuts, no hybrid relief. That gold-bar cost is the whole design. The card exists to reward a manabase that has already solved the hardest problem in the game, which is producing all five colors reliably, and it offers nothing else as compensation: no evasion, no protection, no way to dodge a single removal spell. It is a vanilla beater dressed in the most demanding casting requirement a creature can carry. The body would be aggressively undercosted if that requirement were not the entire balancing mechanism. To a deck that cannot spell WUBRG, it is uncastable; to a deck that can, it is a sledgehammer that asks for nothing back. That binary is the point. Rather than gating the power behind a build-around ability, the design gates it behind the lands and rituals themselves, turning the creature into a kind of payoff trophy: if your mana can produce one of every color, here is your reward, and it is enormous and dumb on purpose.