Maddening Whispers. The abyssal radish telepathically whispers incoherently while it can see any creature and isn't incapacitated. Each creature that starts its turn within 20 feet of the abyssal radish and can hear the whispers must succeed on a DC 15 Wisdom saving throw. On a failure, the creature is stunned until the end of its next turn and the DM rolls a d4 to determine what the whispers say.

On a 1, the whispers tell a truth about the creature that they have no knowledge of.

On a 2, the whispers tell a truth about the creature that they have knowledge of. 

On a 3, the whispers tell a lie to the creature.

On a 4, the whispers are random and chaotic giving the creature no insight.

These whispers could be about the past, present, or even the future. What the context of the whispers are, and how much information is given is to the DM's discretion.

Rejuvenation. When the plant dies, it returns to life in the place where it died 1d12 months later, unless the ground where it took root is sown with salt or soaked with poison.

Unusual Nature. The plant doesn’t require sleep.

Multiattack. The plant makes three Vine Lash attacks. If a creature is grappled, then it can exchange one of these Lashes with an Eat against them.

Vine Lash. Melee Weapon Attack: +7 to hit, reach 20 ft., one target. Hit: 11 (2d6 + 4) slashing damage. If the target is a creature, it is grappled (escape DC 15). Until the grapple ends, the target is restrained. The plant has four vines, each of which can grapple one target.

Eat. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 22 (4d6 + 4) bludgeoning damage. If the target is reduced to 0 hit points then its head is bitten off and consumed, killing them instantly.