This creature appears as a cross between a gnoll female and a bat-winged harpy.
CR 6; XP 6,400
CE Medium Monstrous Humanoid
Init +7; Senses darkvision 60 ft., scent; Perception +15
AC 19, touch 14, flat-footed 15 (+3 Dex, +1 dodge, +5 natural)
hp 67 (9d10+18)
Fort +5, Ref +9, Will +7
Immune harpy's captivating song
Speed 20 ft., fly 80 ft. (average)
Melee bite +12 (2d4+3), 2 talons +12 (1d6+3)
Special Attacks derisive laughter
Spell-Like Abilities (CL 9th, concentration +12)
3/day—ventriloquism (DC 14)
Str 16, Dex 16, Con 14, Int 11, Wis 13, Cha 17
Base Atk +9; CMB +12; CMD 26
Feats Alertness, Combat Reflexes, Dodge, Flyby Attack, Improved Initiative
Skills Fly +15, Intimidate +15, Perception +15, Perform (comedy) +15
Languages Common, Gnoll
SQ sound mimicry
Environment warm plains, deserts, marshes, and mountains
Organization solitary, pair, or a flight (3—12)
Derisive Laughter (Su) Gnoll-harpies laughter has a powerful psychological effect on sapient beings. A gnoll-harpy can target a single enemy within 100 feet as a swift action, or all enemies within the range as a standard action and mock them. On a failed Will saving throw (DC 17), they are either incited or ashamed. Incited targets have to spend their next move action to approach the gnoll-harpy, while ashamed one have to spend their next move action to move away. Lack of shared language gives +4 bonus to the saving throw. This is an emotion mind-affecting effect. Gnoll-harpies are immune to each other's derisive laughter. Once a creature was subject to derisive laughter, successfully or not, it gains +2 bonus to saving throws against it for the next 24 hours.
Gnoll-harpies seem to be descendants of gnoll and harpies mingling, inheriting the worst qualities of both, though that does not explain their completely different wing build—they might be result of some sort of hidden demonic taint among the gnolls, however. They are stronger and more malicious than regular harpies, and more messy and louder than gnolls. They are also vastly more intelligent than either, which baffles sages even more.
They are often at odds with regular harpies, who hate them, though they occasionally cooperate with gnolls, unless deemed abominations by envious shamans.