n medium cold elemental water 

Perception +8; darkvision

Languages Aquan

Skills Acrobatics +7, Athletics +8, Deception +5, Stealth +9, Thievery +7

Str +4 Dex +3 Con +2 Int +0 Wis +2 Cha +1

Recall Reflection (illusion, primal) A ledalusca can recall and replay any reflection ever cast on its surface, although it must still Seek to consciously notice fine or significant details.

AC  17; Fort +8, Ref +9, Will +6

HP 40; Immunities cold, poison, paralyzed, sleep; Weaknesses fire 5

Shell Block [R] Trigger The ledalusca takes physical damage from an attack; Requirements The ledalusca's shell is frozen (see Freeze Shell) Effect The ledalusca angles their shell to absorb the blow, gaining resistance 5 to the triggering damage. If they takes bludgeoning or fire damage after applying this resistance, their frozen shell shatters until they freezes a new one.

Speed 25 feet, swim 30 feet

Melee [>] wave +10, Damage 1d6+4 bludgeoning plus Push 5 feet

Ranged [>] ice shard +9 (deadly d6, thrown 20 feet), Damage 1d6+4 piercing plus 1d4 cold

Melee [>] ice shell +10, Damage 1d6+4 physical plus 1d4 cold

Freeze Shell [>] (cold, manipulate) The ledalusca freezes their surface into a translucent, faintly colored ice sculpture matching the mirror image of a Medium creature or object they have seen before. While in this form, instead of a wave, they have the following Strike: Melee [>] ice shell +10, Damage 1d6+4 physical plus 1d4 cold The physical damage is a type that matches the new shape of the ledalusca's frozen shell. The ledalusca can revert to their liquid form by taking this action again.

Hold Still [>] (concentrate) Until the next time they act, the ledalusca appears to be either an ice sculpture (if under the effects of Freeze Shell) or a pool of still water (if not). They have an automatic result of 28 on Deception checks and DCs to pass as what they appear to be.

Bestiary 3, page 159.