Merciless Monsters 12: Rotocula (Female)

The Rotocula, as illustrated by cbMorrie
The Rotocula, as illustrated by my ladyfriend, cbMorrie

The Rotocula is a sexually dimorphic creature which makes its home in mud flats. The adult forms of the male and female are so different that they have often been confused for completely different species. As such, they warrant separate monster entries. The male was posted last week.

Like her male counterpart, the bulk of the female rotocula appears to be a large pile of sagging mud. The female also shares the male’s unique rolling-orb appendages, which serve as organic wheels that provide the rotocula with mobility. The similarities between the two do not go far beyond that, however.

The female of the species has no legs. Nor does it share the male’s tough skull structure. Nor does it spend most of its time at rest while camouflaged. Quite the opposite! From the moment a female rotocula rises in the morning, to the moment it digs a small muddy pit to sleep in, the creature howls across the plains. The female’s constant screeching is meant to terrify its prey into running, as the female actually finds it more difficult to attack creatures at rest.

The beast’s mouth completely separates the left and right halves of its head, and can potentially open so wide that the tips of the teeth are behind the esophagus. This, in conjunction with the rotocula’s long prehensile tongue, allows prey to be consumed without subduing it first. The female merely positions itself being a running creature. Then, using her immense speed, she surges forward, trapping the fleeing meat within her jowls.

While there is a skull-like bone mass on each side of the female’s head, only one side contains a brain. And, curiously, which side of the head the brain is on varies between individual specimens. The only noticeable effect of this is that one of the rotocula’s eyes (due to the long path the optic nerve must travel) is often much weaker than the other. It sees only vague blurs of color and motion. There is no simple way to determine which eye is weaker, but if it is discovered, it could give those wishing to fight the beast an advantage.

Female rotocula have a distinctive patch on their back which is a smooth brown and tan. When they wish to mate, they raise their tail to display its underside (as shown). The sight of this long patch of smooth skin–in conjunction with a differently pitched howling the female emits–entices males to approach. The female then opens her mouth as wide as possible, and the male inserts his snout into her throat. Once the act is complete, the female’s jaws snap closed, killing their mate.

Female Rotocula

A loud screeching howl alerts you to the presence of a mud colored mass with razor teeth speeding towards you.

Rotocula; CR 14; [Aberration] [Mud Flats] [Diurnal]

XP: 38,400
N Huge Aberration
Init +10; Senses Perception +8


AC 11, touch 11, flat-footed 6 [10 + Dex(-2) + Size(-2) + Natural(5)]
HP 217 (16 HD, 16d8 + 176)
Fort +21 Ref +3 Will +2;


Speed 120ft (1ft on non-flat ground, cannot climb even simple structures)
Melee Slam + 24 (2d8 + 10)
Melee Bite + 28 (6d10 + 12) [A bitten creature may be grappled as a free action]


Str 35 Dex 6 Con 33 Int 2 Wis 3 Cha 4
BAB +16/11/6/1; CMB 28; CMD 36
Languages None
SQ Running Start, Swallow Whole, Attract Male


Biting Charge(Ex) Like her male counterpart, the female Rotocula’s slam attack is greatly enhanced if it has enough space to build momentum. The effect can be even more devastating for the female, given that her powerful jaws are positioned at the front of her mass. If the female Rotocula makes a 50ft charge in a straight line prior to a bite attack, then she is granted an additional +6 to her attack roll.

Swallow Whole(Ex) If the female Rotocula begins a turn with an opponent grappled in its mouth, it can attempt a combat maneuver check. If the check succeeds, the grappled character takes bite damage, and is swallowed. Character must be of large size or smaller to be swallowed whole. Swallowed creatures are considered grappled, and take 5d6 acid damage each turn until they die, or escape. The armor class of the inside of a Rotocula is 12. A hole can be cut in the Rotocula from the inside by dealing 20 hit points of damage.

Attract Male(Ex) If in dire need, a female Rotocula may raise her tail and issue a mating roar. If the creature is encountered in its natural environment, there is a one-time chance that there is a male Rotocula nearby who will respond to the call and come defend its potential mate. Roll 1d20:

  • 1-13; No male Rotocula are nearby.
  • 14-17; a single male Rotocula comes to assist. (Will arrive in 1d6 rounds)
  • 18-19; two male Rotocula come to assist. (Each will arrive in 1d6 rounds)
  • 20; three male Rotocula come to assist. (Each will arrive in 1d6 rounds)


Environment Mudflats. Very occasionally found in areas of plains.
Organization Solitary
Activity Cycle Diurnal
Diet Any living creature of small large or smaller; Natural Enemies Dragons
Treasure None

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4 thoughts on “Merciless Monsters 12: Rotocula (Female)”

  1. I like these two! It was weird reading at first because I thought these would be Medium; them being Huge caught me completely off guard. You mentioned in the Male article that they were afraid of the Females. I’m guessing that comes from knowing mating will end their lives or because the Females are big and scary?

    In any case these look they’d be fun to run at the table, though probably not til houseruling Swallow Whole to be more deadly. I’m personally no longer a fan of the “I was swallowed so wait 20 seconds and this thing will be dead FROM TEH INSIDE!” trope.

    1. Glad you’re a fan! Its an idea that has been bouncing around in my head for the better part of a decade. I won’t say they’re the best monsters I’ve ever come up with, but I like them all the same.

      You make a good point about Swallow Whole. I basically drew that word-for-word from the PF Bestiary’s list of monster abilities. But like you, I feel as though attacking a creature from the inside should be an immense feat. Not something you’re simply allowed to do once you’re swallowed.

      1. Glad to see I’m not the only one! One of my AD&D players was in a game recently (I believe it was 3e… not sure) where he killed a T. Rex from the inside. It sounded really cool, but he talked as if cutting himself out was a foregone conclusion, and that’s just not something I’m okay with.

        Whereas I’m tempted to just never have a monster try to eat a living character, I think that could take away something from the table, so i needed to find something better to use. I think the best I have seen involves the character having to make a fortitude save vs. acid every round, then make the grapple check, then get a penalty to their attack roll, and require a good number of HP loss on the part of the beastie for the character to have a hole big enough to crawl out of.

        1. Depending on the deadliness of your rules, you could simply have the character make a save v. death when eaten. Failure means they were chomped to bits on the way into the monster’s gullet. Success means they get to brave constant acid damage, str check to hold on to their weapon, and a -X to damage rolls.

          That ought to make it hard enough to escape!

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