Advanced Telepathy. The flumph perceives the content of any telepathic communication within 60 feet of it.
Prone Deficiency. If the flumph receives the Prone condition, roll a die. On an odd number, it has the Incapacitated condition. At the end of each of its turns, the flumph makes a DC 10 Dexterity saving throw, ending the Incapacitated condition on a success.
Telepathic Shroud. The flumph's thoughts can't be read by any means, and magic can't detect its location or observe it remotely.
Tentacle. Melee Attack Roll: +4, reach 5 feet. Hit: 4 (1d4 + 2) Acid damage.
Stench Spray (1/Day). Dexterity Saving Throw: DC 10, one creature the flumph can see within 15 feet. Failure: The target is coated in a foul-smelling liquid, exudes a stench for 1d4 hours, and has the Poisoned condition while the stench lasts. Other creatures have the Poisoned condition while in a 5-foot Emanation originating from the coated target. The target can remove the stench on itself if it bathes during a Short or Long Rest.