Berrydra

Multiple Heads. The berrydra has three heads. Whenever the berrydra takes 15 damage or more on a single turn, one of its heads dies. The berrydra dies if all its heads are dead. At the end of each of its turns when it has at least one living head, the berrydra grows two heads for each of its heads that died since its last turn, unless it has taken Fire damage since its last turn. The hydra regains 10 Hit Points when it grows new heads.

Reactive Heads. For each head the berrydra has beyond one, it gets an extra Reaction that can be used only for Opportunity Attacks.

Regurgitate. When the berrydra is bloodied for the first time in combat, it regurgitates eaten berries onto the ground in a 10-foot-radius-area in front of itself.
The area becomes difficult terrain for 1 minute. The berrydra is immune to all effects of this terrain.
Any other creature that enters the area for the first time on a turn or starts its turn there must succeed on a DC 14 Dexterity Saving Throw or fall prone.

Multiattack. The berrydra makes as many Bite attacks as it has heads.

Bite. Melee Attack Roll: +5, reach 5 ft. Hit: 8 (1d6 + 5) Piercing damage.