Living Branches. The branches of the viper tree are multicolored snakes. While the tree has hundreds of branches, the viper tree can only control up to 5 at a time. Each branch can be attacked (AC 20; 12 hit points; same immunities and vulnerabilities as the viper tree). Destroying a branch deals no damage to the viper tree. If a branch is destroyed, another one takes it place on the viper tree's next turn.

Multiple Heads. Due to the viper tree's multiple heads, it has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious. 

Multiattack. The viper tree makes as many bite attacks as it has active branches.

Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one creature. Hit: 10 (1d10 + 5) piercing damage plus 7 (2d6) poison damage, and the target must succeed on a DC 15 Constitution saving throw or their Dexterity score is reduced by 1d4. The target dies if this reduces its Dexterity to 0. Otherwise, the reduction lasts until the target finishes a short or long rest.