Thrasfyr

The thrasfyr always treats the plane it is located on as its home plane.

A constant spell affects the monster without the monster needing to cast it, and its duration is unlimited. If a constant spell gets counteracted, the monster can reactivate it by spending the normal spellcasting actions the spell requires.

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.

The thrasfyr's serpent tail breathes a blast of flame in a 50-foot cone, dealing 10d12 fire damage (DC 40 basic Reflex save).

It can't use Breath Weapon again for 1d4 rounds.

The thrasfyr designates one creature as its rider by touching the rider with its claw. The thrasfyr and rider can communicate with each other telepathically at any range on the same plane and are aware of each other's present state, direction from each other, distance from each other, and any conditions affecting either.

The thrasfyr thrashes its chains in all directions. Each creature in a 15-foot emanation takes 18d6 bludgeoning damage (DC 38 basic Reflex save); creatures that fail are Immobilized until the start of the thrasfyr's next turn.

The thrasfyr can't use Tangling Chains or make chain Strikes for 1d4 rounds.

The thrasfyr makes a jaws Strike, a horn Strike, and two claw Strikes, each against a different target. Each attack counts toward the thrasfyr's multiple attack penalty, but the penalty doesn't increase until after all the attacks.