Nimble Escape. The green gremlin can take the Disengage or Hide action as a bonus action on each of its turns. 

Spider Climb. The green gremlin can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Multiattack. The green gremlin makes two attacks: one bite attack and one claws attack or two attacks with weaponized bric-a-brac.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) piercing damage, and the target must succeed on a DC 11 Wisdom saving throw or become frightened for 1 minute. A frightened victim must take the Dash action to move away from the green gremlin on each of its turns, unless there is nowhere to move. If the target ends its turn in a location it doesn't have line of sight to the gremlin, it can make a Wisdom saving throw, ending the fear effect on itself on a success.​

Claws. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (2d4 + 1) slashing damage.

Weaponized Bric-a-Brac. Melee or Ranged Weapon Attack: +3 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 3 (1d4 + 1) damage of randomly determined type: roll d4; a result of 1-2 is bludgeoning, 3 is slashing, 4 is piercing.​