Chac (5e Creature)

Medium elemental (shapechanger), neutral

Armor Class 13
Hit Points 13 (2d8 + 4)
Speed 30 ft., swim 30 ft. (40 ft. in jaguar form)

Skills Perception +3, Stealth +5
Proficiency Bonus +2
Senses darkvision 60 ft., passive Perception 13
Languages any one language (usually Payit)
Challenge 1/2 (100 XP)

Amphibious. The chac can breathe air and water.

Innate Spellcasting. The chac's innate spellcasting ability is Wisdom (spell save DC 11). The chac can innately cast the following spells, requiring no material components:

At will: control water, water walk
3/day: gaseous form
1/day: control weather

Shapechanger. The chac can use its action to polymorph into a jaguar, or back into its true form, which is humanoid. Its statistics, other than its movement speeds, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Keen Smell. The chac has advantage on Wisdom (Perception) checks that rely on smell.

Pounce (Jaguar Form Only). If the chac moves at least 20 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 13 Strength saving throw or be knocked prone. If the target is prone, the chac can make one claw attack against it as a bonus action.

A chac in her humanoid form flanked by one in its jaguar form, source

A chac (plural chacna) is a beast-like creature native to all parts of Maztica. While chacna often take the form of slender jaguars or jaguar-like humanoids, it is more accurate to describe them as water spirits. Chacna have a high degree of control over water, especially rain, which they treat as a paintbrush on the canvas of the world below them from the peaks and tree tops they make their lairs. This focus on beauty extends into all aspects of chac society, to such an extent that the only time a chac will willingly enter a settlement is to trade for artwork.
Chacna are skittish, fearful creatures, and will almost never fight if it has the opportunity to run. This has served them greatly, as the skin and claws of a chac are powerful components for a hishnashaper, while their control over the weather makes a captured chac a valuable asset to many village Councilors. Half of all chacna worship the primal spirits, or rather venerate greater spirits that they themselves descend from, while the other half worship Azul, the Giver of Rain. Primal chacna can typically be appeased or ingratiated through offerings of food and art at the foot of their lair, while Azulian chacna can only be appeased through worship of Azul. Azulian chacna also have a unique relationship with tlalocoatl, being guarded by them rather than hunted like their primal cousins.
Chacna can typically be identified by the steam of tears that permanently run down their face, though it is actually the ceasing of these tears that denotes sorrow in a chac. There are five sub-species of chac, each denoted by the color of their eyes and gaseous form, and the dominant color in their collected artwork: the blue chac of Northern Maztica, the red chac of Southern Maztica, the green chac of Eastern Maztica, the yellow chac of Central Maztica, and the black chac of Far Payit and Lopango. While no hostility has been observed between these groups, neither has one sub-species inhabiting another's territory.
Chac reach maturity at about 5 years of age, and can go on to live over 100 years. A chac can sustain itself entirely on water, but finds much pleasure in consuming food. The birth of a chac is a lengthy process, involving a pair of chac that have reached reproductive age, typically at least 50 years old, mingling essences in their gaseous forms. The offspring then gestates for an entire year, at the end of which a great celebration is performed, gathering chacna from the entire region to witness the birth and rejoice with a great storm. It is often only at such a celebration that chac meet one another, often resulting in the formation of one new couple. The newborn chac is protected by both of its parents until it reaches maturity.