Elemental

Elemental refers to both a type of creature, and to the specific incarnations of the for classical elements: air, earth, fire, and water.

General Characteristics
Elementals are manifestations of an element. On their home planes, they are formless spirits unless focused by magic, and they are analogous to animals on the Material Plane in their motivations and sentience. All are immune to poison, resistant to physical damage from nonmagical sources; and cannot be exhausted, paralyzed, petrified, or knocked unconscious.

Air Elemental
Air elementals have tornado or whirlwhind-like appearance, with a barely-perceptible face.

Earth Elemental
Earth elementals have a vaguely humanoid shape, but are made of dirt and stone.

Fire Elemental
Fire elementals set their surroundings alight, and can be stopped with water.

Water Elemental
Water elementals are shaped like tidal waves and can engulf their foes.

Notable Elementals
As a Circle of the Moon druid, Keyleth could wildshape into elemental form, and often did so in combat. Vox Machina encountered elemental foes several times, notably fire elementals at the portal to the Elemental Plane of Fire in Pyrah, and water elementals as they approached Vesrah. Keyleth's Spire of Conflux also had the capacity to conjure elementals.

The Mighty Nein also faced elementals in the fight in which they freed Xundi, and fought them several times in Eiselcross. Beau had an elemental gem looted from the Sour Nest which permitted her to summon a fire elemental, which she did against Thelashas.