Biomass Blight

False Appearance. While the blight remains motionless, it is indistinguishable from a green ooze

Hivemind. All attempts to commune telepathically and all the things this creature experiences are directed back to the Biomass that created it.

Corrode Metal: Any nonmagical weapon made of metal that hits the ooze 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 that hits the ooze is destroyed after dealing damage.
The ooze can eat through 2-inch-thick, nonmagical metal in 1 round.

Poisonous Seize. Melee Weapon Attack +7 to hit, reach 5 ft., one creature. Hit 7 (1d4 + 5) poison damage. Target is grappled.

Blob launch. Ranged Weapon Attack: +3 to hit, range 120 ft., 1 target. Hit: 5 (1d8 + 3) [poison] damage.