Arc Runner

Five power for three mana with haste is a ratio almost nothing else in red touches, and the reason is printed two lines down: at the beginning of every end step, the creature sacrifices itself. This is not an attacker you keep, it is a single swing rented at full retail. With only 1 toughness it dies to almost any block, but that hardly matters: it was always leaving at the end step regardless, so trading it in combat just speeds up an exit that was already scheduled. The body cannot stick around to block, chump, or untap into a second attack, which is what makes the rate so lopsided. That is an old red bargain (pay now, lose it later) stretched to an unusually aggressive number, and the honest question it asks is whether five damage on the turn it lands closes a gap that matters, because that one swing is the entire return on the mana. Two things complicate the clean burst. First, without trample any lone 1/1 chump-blocks it into nothing, so the five power only reads as five damage when the path is genuinely clear. Second, the sacrifice is a cost you can sometimes capture rather than waste: a sacrifice outlet that wants a fresh body, or an effect granting an extra combat that same turn, converts the doomed creature into value it was going to surrender anyway. Flickering it does not break the leash, since the end-step trigger fires every turn; a blink only postpones the sacrifice rather than retiring it.