Taiga Yai

Greater Darkvision — A creature with greater darkvision can see perfectly well in areas of darkness and dim light, though such vision is in black and white only. A creature with greater darkvision can see through even forms of magical darkness.

Botanic Interruption (primal) —

Constant Spells — 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.

+1 Status to All Saves vs. Magic —

Regeneration 15 (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 —

Change Shape (concentrate, polymorph, primal) — The taiga yai takes on the appearance of a Taiga Giant. This doesn't change their Speed or Strike attack and damage.

The monster changes its shape indefinitely. It can use this action again to return to its natural shape or adopt a new shape. Unless otherwise noted, a monster cannot use Change Shape to appear as a specific individual. Using Change Shape counts as creating a disguise for the Impersonate use of Deception. The monster's transformation automatically defeats Perception DCs to determine whether the creature is a member of the ancestry or creature type into which it transformed, and it gains a +4 status bonus to its Deception DC to prevent others from seeing through its disguise. Change Shape abilities specify what shapes the monster can adopt. The monster doesn't gain any special abilities of the new shape, only its physical form. For example, in each shape, it replaces its normal Speeds and Strikes, and might potentially change its senses or size. Any changes are listed in its stat block.

Return to Nature (earth, manipulate) — The taiga yai commands underground plant roots to drag a creature within 60 feet into the earth. The target must succeed at a DC 35 Fortitude save or be Immobilized for 1d4 rounds. After this time, the creature is buried; it is Grabbed, begins to suffocate, and takes 4d6 bludgeoning damage each round they remain buried. To escape either while immobilized or grabbed, the creature must succeed at a Escape check or an adjacent ally must succeed at a DC 33 Athletics check to pull them out.