Vrock

Toxic Spores, the ability word threading a small cluster of these fiends together, wraps a trigger broader than a death-drain: "a permanent you controlled left the battlefield this turn" catches any zone change, not just creatures dying. A sacrificed Treasure counts. A fetchland cracked for its land counts. A creature flickered to exile and returned counts (a phased-out permanent does not, since phasing is not leaving the battlefield). The load-bearing detail is the intervening 'if' clause: the condition must already be true once your end step begins, so the trigger reads the turn that has happened rather than the events it is about to spawn. Anything that leaves as the end step opens (fodder you sacrifice then, tokens that expire in cleanup) arrives too late to count for that turn. That makes this a retrospective drain, auditing whether your board churned before the end step, and pinging each opponent for three if it did. The loss caps once per turn and returns nothing to you: opponents bleed, you gain no life, so the effect is a table-wide clock, not a stabilizing valve. The 3/3 flier is undersized for five mana, which puts the whole case on that audit. It wants a sacrifice outlet and a steady supply of spent artifacts and dying tokens earlier in the turn, converting an aristocrats deck's ordinary attrition into reach. Read it as a drain engine wearing wings, not a beater that happens to bleed.