Ambusher. In the first round of a combat, Clonk has advantage on attack rolls against any creature it surprised.
Mimicry. Clonk can mimic any sounds it has heard, including voices. A creature that hears the sounds can tell they are imitations with a successful DC 14 Wisdom (Insight) check.
Hellfire Warhammer. Melee Weapon Attack: +2 to hit, reach 5 ft., one target. Hit:4 (1d8) bludgeoning damage, or 5 (1d10 + 1) bludgeoning damage if used with two hands to make a melee attack.