Thriving Skyclaw

The energy it hands you covers exactly one pump: three counters in, three counters spent, a 3/2 flier that grows to a 4/3 the first time it swings. And note the timing there, because it matters more than it looks. The +1/+1 counter goes on during the declare attackers step, before blockers are chosen, so the creature is already 4/3 when your opponent decides whether and how to block. On its own, it is a slightly overcosted evasive body with a single size bump built in. The interesting seam is that the energy is fungible. Nothing about those three counters is earmarked for the attack trigger; they are the same generic resource a whole family of red and multicolor cards produce and consume, which turns a standalone creature into a battery. Surround it with other energy generators and the attack tax gets paid every turn instead of once; drop it into a shell that wants energy for something else entirely and it becomes a ramp piece that happens to fly. That dual nature, self-sufficient in isolation but a node in a larger engine when supported, gives it a range that the many red four-drops relying on hardcast mana to grow never had. The +1/+1 counter it stacks is permanent, so a long game lets the flier outscale its printed line without ever leaning on the rest of your board.