Hellhole Rats

The damage is metered by the victim, not the caster. Forcing a discard and dealing damage equal to the discarded card's mana value hands the targeted player the choice of what to pitch, which means the worst case is a land or a cantrip ditched for one or zero damage, and the best case is an opponent caught holding nothing but expensive bombs. That variance is the whole design: a hasty 2/2 that can close a game when the discard lands on a six-drop, and a glorified hand-disruption blip when it does not. The card sits at an awkward seam between the two effects black and red trade in: targeted discard and direct damage. Most cards that do both let you aim them; this one outsources the targeting to the player least inclined to cooperate, who will always hand over their cheapest card. The reward for that loss of control is doing two disparate jobs on one body, with haste to start chipping the moment the trigger resolves. It is at its sharpest against an opponent down to a single card, where the choice of what to discard disappears and the damage is whatever they were forced to keep: a topdeck war, where a few points to the face matter most, is exactly the spot this rat was built to punish.