Clathrus Sprout

Amorphous. Clathrus Sprout can move through a space as narrow as 1 inch wide without squeezing.

Corrosive Form. A creature that touches Clathrus Sprout or hits it with a melee attack while within 5 feet of it takes 4 (1d8) acid damage. Any nonmagical weapon made of metal or wood that hits Clathrus Sprout corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed.

Nonmagical ammunition made of metal or wood that hits Clathrus Sprout is destroyed after dealing damage.

Spider Climb. Clathrus Sprout can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Legendary Resistance (2/Day). If Clathrus Sprout fails a saving throw, it can choose to succeed instead.

Magic Resistance. Clathrus Sprout has advantage on saving throws against spells and other magical effects.

Magic Weapons. Clathrus Sprout’s weapon attacks are magical.

Mycelium Regeneration. Clathrus Sprout regains 10 hit points at the start of its turn. If it takes fire or radiant damage, this trait doesn’t function at the start of its next turn. Clathrus Sprout dies only if it starts its turn with 0 hit points and doesn’t regenerate.

Multiattack. Clathrus Sprout makes 2 pseudopod attacks.

Pseudopod. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 5) bludgeoning damage plus 18 (4d8) acid damage. In addition, nonmagical armor worn by the target is partly dissolved and takes a permanent and cumulative −1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.

Clathrus Sprout can take 2 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. Clathrus Sprout regains spent legendary actions at the start of its turn.

Attack. Clathrus Sprout makes one pseudopod attack.

Acid Splash. Clathus Sprout casts acid splash.