Illumination. The Volcano snail emits a dim fire-like light in a 20ft radius.

Melee: (+4 to hit) Extends its sclerites to swing for 2d6 bludgeoning damage. A creature hit by this will burn and take 1d6 fire damage at the end of each turn.

Midrange Melee: (+5 to hit) The snail extends a harpoon-like proboscis at a target in front of it within 10 feet. A player hit by this will take 3d6 piercing damage.

Ranged: (+6 to hit) Magma bombs. The snail ejects 3 small rocks at one or more targets. Each magma bomb explodes with intense heat and does 3d8 fire damage.

Mastery of senses: The snail can use a bonus action to anticipate an attack from one target for advantage on saving throws when it gets attacked next by that target. The target doesn't know its being sensed.

Retreat!: The snail can hide in its shell, as long as it is in its shell, it can't attack, and must use an action to return to combat. While in its shell it has +4 to AC.