Reiver Demon

The trigger is wired with a condition most board wipes never carry: it only fires when cast from hand, which means a reanimated Reiver Demon arrives as nothing but a 6/6 flier. That single clause reshapes the entire deckbuilding proposition. The obvious play (cheat it into play early) is exactly the play the card refuses to reward, forcing you to cast it from hand the hard way to get the sweeper attached. The wipe itself is asymmetric in a way a black artifact-heavy shell can exploit: black creatures and artifact creatures survive on both sides, and regeneration is denied, so the board you keep is whatever you built to keep. That asymmetry cuts toward your own survivors, not against opposing artifact armies; an enemy board of artifact creatures walks away clean, which makes the demon a poor answer to the metalcraft-style aggression of its era and a strong reward for a mono-black build full of black bodies. The double edge is that the 6/6 flier and the board wipe are sold as a package only when cast from hand; any shortcut to the battlefield buys you the worse half. A demon that punishes the very thing demons are usually played to do (skip their cost) is a tidy bit of design tension, and it makes Reiver Demon a more honest card than its raw rate suggests.