Riot Spikes

The +2/-1 split is a deliberately lopsided trick: it adds enough power to push a creature over the top in combat while shaving a toughness, which means it doubles as a removal spell against anything with one toughness left. Cast it on your own attacker and it is a cheap pump; cast it on an opposing X/1 (or a blocker already chipped down) and it is a kill spell wearing a buff's clothing. That dual purpose is what the hybrid casting cost is built to enable: payable with either black or red, it slots into the aggressive end of either color without asking for both, so a mono-red beatdown deck and a black-based aggro deck can each run it as the same card doing slightly different jobs. The drawback is the same thing that makes it flexible: it is an Aura, so it carries the two-for-one risk every Aura does. Bounce, removal, or a sacrifice in response to its resolution costs you the card and the creature both, and the toughness reduction can backfire by leaving your own creature one removal spell (or one point of damage) from death. As a one-mana enchantment it is closer to a creature-modifying spell that happens to stick around, rewarding decks that want to commit to a board and tilt every combat math problem two points in their favor.