Monster multiplying on damage

[BenTheJester]

Are there any monster that multiplies when it takes damage(ie: you hit it, now there's 2 of it)?

[Cog]

Oozes (http://www.d20srd.org/srd/monsters/ooze.htm) (though not all of them) are the classic example.

[Dimers]

The CR2 "trap" brown mold (http://www.d20srd.org/srd/dungeons.htm) is something like that.

[Darrin]

Are there any monster that multiplies when it takes damage(ie: you hit it, now there's 2 of it)?

Black Pudding and Ochre Jelly are both in the SRD.

The problem with most splitting oozes is diminishing returns... the HP total only goes down, so yeah, there may be more oozes, but even the Black Pudding (115) can only split at most 4 times (16 black puddings) before each mini-pudding is below 10 HP.

The Void Ooze (Planar Handbook p. 133) has a different Split (Ex) mechanic... it has an energy drain attack, and every time it bestows a negative level, it gains 5 HP. When it reaches 200 HP, it splits into two Void Oozes with 100 HP.

However, I haven't come up with a reliable way to "feed" it quickly enough... as a large creature, it can drain at least four medium-sized creatures by engulfing all four on the same round, but that's only 20 HP per round. Maybe a warlock with summon swarm...? Can it gain 5 HP per creature in the swarm, or is the swarm treated as "one creature" for the purposes of energy drain?

Hmm... but if it engulfs a Dread Necro with Tomb-Tainted Soul, or maybe four of them... now that gets a little interesting.