Awkward Flier. The abyssal untitled Goose falls at the end of a turn if it’s airborne and fails a Dex Check (15) and the only thing holding it aloft is its flying speed.

Multiattack. The abyssal Goose makes two attacks: one with its bite and one with its claws.

Bite. Melee Weapon Attack: +6 to hit, reach 10 ft., one creature. Hit: 4 (2d4 + 4) piercing damage.

Claws. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 5 (2d6 + 4) slashing damage.

Fire Breath: AoE Attack: +6 to hit, reach 20 ft. up to six targets. Hit: 6 (2D8 + 6) fire damage. 

Sonic Honk: Cone Attack: +4 to hit, reach 20 ft. up to four targets. Hit: 8 (2D8 + 4) psychic damage. If hit, target is incapacitated for one round. If Goose crits, then target is incapacitated for up to three rounds of combat. Target can make a CON save throw (16)

Goose will focus on NPC or PC that attacks them directly for 1-3 turns of combat. If NPC or PC attacks a clutch of eggs, or goslings; Goose will be open to attacks of opportunity as it focuses attacks and attention on attacking NPC or PC. 

Goose rears back it's head, opens its vile maw and either spews fire  up and outward in a rain, or may aim at a NPC or PC attacking it directly.