Corusdeers

Can cast Fog Cloud at will
You create a 20-foot-radius sphere of fog centered on a point within range. The sphere spreads around corners, and its area is heavily obscured. It lasts for the duration or until a wind of moderate or greater speed (at least 10 miles per hour) disperses it.


Can cast Cloudkill at will
You create a 20-foot-radius sphere of very cold, snowy fog centered on a point you choose within range. The fog spreads around corners. It lasts for the duration or until strong wind disperses the fog, ending the spell. Its area is heavily obscured.

When a creature enters the spell's area for the first time on a turn or starts its turn there, that creature must make a Constitution saving throw. The creature takes 5d8 fire damage on a failed save, or half as much damage on a successful one. Creatures are affected even if they hold their breath or don't need to breathe.

The fog moves 10 feet away from you at the start of each of your turns, rolling along the surface of the ground. The vapors, being heavier than air, sink to the lowest level of the land, even pouring down openings.

Action Melee Attack. Melee Weapon Attack: +5 to hit, reach 5 ft., 1 target. Hit: 10 (2d8 + 5) [Slashing] damage. If the Corusdeer has ignited its horns it also does 2d6 Fire damage

Can ignite its horns to do an additional 2d8 fire damage on top of regular damage this lasts 1 minute

You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature. The attack occurs right before the creature leaves your reach.