Rampage. When the witherling reduces a creature to 0 hit points with a melee attack on its turn, it can take a bonus action to move up to half its speed and make a bite attack.
Multiattack. The witherling makes two attacks: one with its bite and one with its club, or two with its club.
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit:4 (1d4 + 2) piercing damage.
Club. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit:4 (1d4 + 2) bludgeoning damage.
Vengeful Strike. In response to a gnoll being reduced to 0 hit points within 30 feet of the witherling, the witherling makes a melee attack.
Sometimes gnolls turn against each other, perhaps to determine who rules a war band or because of extreme starvation. Even under ordinary circumstances, gnolls that are deprived of victims for too long can't control their hunger and violent urges. Eventually, they fight among themselves.