Ouroboros

+1 Status to All Saves vs. Magic —

Regeneration 50 (Deactivated by Fire) — This monster regains the listed number of Hit Points each round at the beginning of its turn. Its Dying condition never increases beyond Dying 3 as long as its regeneration is active. However, if it takes damage of a type listed in the regeneration entry, its regeneration deactivates until the end of its next turn. Deactivate the regeneration before applying any damage of a listed type, since that damage might kill the monster by bringing it to Dying 4.

Attack of Opportunity (Special) — Incalculable Fangs Only

Because the ouroboros contains an infinite number of snakes that act independently, its Attack of Opportunity is a free action (though it can still use only one per trigger).

Trigger A creature within the monster's reach uses a manipulate action or a move action, makes a ranged attack, or leaves a square during a move action it's using.

Effect The monster attempts a melee Strike against the triggering creature. If the attack is a critical hit and the trigger was a manipulate action, the monster disrupts that action. This Strike doesn't count toward the monster's multiple attack penalty, and its multiple attack penalty doesn't apply to this Strike.

Sanguine Spray — When the ouroboros takes slashing or piercing damage, or when Devour Tail ends, blood gushes from the wound in a 15-foot cone. Each creature in the area takes 5d6 acid damage (DC 41 Reflex save). A creature that takes any damage is exposed to the ouroboros's regenerative blood.

Where the blood falls upon ground, it coagulates into magical snakes that bite at anyone who passes. This is hazardous terrain deals 17 piercing plus 5 poison{17 piercing damage and 5 poison damage} to any non-ouroboros creature that moves through the square or ends its turn there. A creature that avoids all the piercing damage doesn't take the poison damage. After 1 hour, a blood patch permanently becomes a living snake, typically an Emperor Cobra.

Unfathomable Infinity (aura, incapacitation, mental, visual) — 100 feet. The ouroboros is the embodiment of perfect infinity, and this concept pulls at the threads of mortal minds, desperately straining the limits of their comprehension. When a creature ends its turn in the aura, it must attempt a DC 41 Will save.

The creature is then temporarily immune for 1 minute.

Critical Success The creature is Stupefied 1 for 1 round.

Success The creature is stupefied 1 for 1 minute.

Failure The creature is stupefied 1 for 1 minute and Stunned 3.

Critical Failure The creature is Stupefied 3 and Stunned, both for 1 minute.

Devour Tail — An ouroboros spend most of its life eating its own tail, which perpetually regrows at the same rate it's consumed. The ouroboros places its maw around the end of its tail and begins devouring its own body.

While the ouroboros is consuming itself, its regeneration can't be suppressed, and it is immune to Drained, Enfeebled, Fatigued, Persistent Damage, and Sickened conditions. If any of these conditions is in effect when the ouroboros takes this action, the condition immediately ends.

While eating its tail, the ouroboros can't make maw or tail strikes, and its Speeds are 50 feet. It continues devouring its tail even while Dying, Unconscious, Stunned, or otherwise unable to act.

To end this effect, the ouroboros must first be Immobilized, then a creature must successfully Grapple it, which tears the maw free in addition to its normal effects. The ouroboros can also cease Devouring its Tail with a single action. Either of these tears the maw free of the tail, causing the stump to spill blood as described in sanguine spray.

Fast Swallow —

Flying Wheel — Huge or smaller, body, DC 45 Reflex

The monster Strides up to double its Speed and can move through the spaces of creatures of the listed size, Trampling each creature whose space it enters. The monster can attempt to Trample the same creature only once in a single use of Trample. The monster deals the damage of the listed Strike, but trampled creatures can attempt a basic Reflex save at the listed DC (no damage on a critical success, half damage on a success, double damage on a critical failure).

Regenerative Blood (contact, curse, incapacitation, poison, polymorph, primal) — The regenerative and transmutative properties of ouroboros blood regenerate and mutate a creature's body into ouroboros-like snakes. A creature already affected by regenerative blood is immune to additional exposure.

Saving Throw DC 42 Fortitude

Maximum Duration 24 hours

Stage 1 regeneration 5 (deactivated by fire), Slowed 1, and Clumsy 2 (12 hours)

Stage 2 regeneration 5 (deactivated by fire), Slowed 2 and Clumsy 4 (12 hours)

Stage 3 The creature's body transmutes into a mass of writhing snakes, with the effects an 8th-rank Animal Form spell but with an unlimited duration.

Swallow Whole (attack) — Huge, 4d10+9 acid, Rupture 50

The monster attempts to swallow a creature of the listed size or smaller that it has grabbed or restrained in its jaws or mouth. If a swallowed creature is of the maximum size listed, the monster can't use Swallow Whole again. If the creature is smaller than the maximum, the monster can usually swallow more creatures; the GM determines the maximum. The monster attempts an Athletics check opposed by the grabbed creature's Reflex DC. If it succeeds, it swallows the creature. The monster's mouth or jaws no longer grab a creature it has swallowed, so the monster is free to use them to Strike or Grab once again. The monster can't attack creatures it has swallowed.

A swallowed creature is Grabbed, is Slowed 1, and has to hold its breath or start suffocating. The swallowed creature takes the listed amount of damage when first swallowed and at the end of each of its turns while it's swallowed. If the victim Escapes this ability's grabbed condition, it exits through the monster's mouth. This frees any other creature grabbed in the monster's mouth or jaws. A swallowed creature can attack the monster that has swallowed it, but only with unarmed attacks or with weapons of light Bulk or less. The swallowing creature is Off-Guard against the attack. If the monster takes piercing or slashing damage equaling or exceeding the listed Rupture value from a single attack or spell, the swallowed creature cuts itself free. A creature that gets free by either Escaping or cutting itself free can immediately breathe and exits the swallowing monster's space.

Effect: Engulf and Swallow Whole

If the monster dies, a swallowed creature can be freed by creatures adjacent to the corpse if they spend a combined total of 3 actions cutting the monster open with a weapon or unarmed attack that deals piercing or slashing damage.

Improved Grab —