Nyth (CR 5)

Small Aberration
Alignment: Usually lawful evil
Initiative: +9 (Dex); Senses: Listen +11 and Spot +11
Languages: Common and can communicate with will-o'-wisps

AC: 24 (+1 size, +9 Dex, +4 deflection), touch 24, flat-footed 15
Hit Dice: 7d8 (31 hp)
Fort +2, Ref +13, Will +8
Speed: Fly 50 ft. (perfect)
Space: 5 ft./5 ft.
Base Attack +5; Grapple -1
Attack: Bite +15 melee
Full Attack: Bite +15 melee
Damage: Bite 1d6+2
Special Attacks/Actions: Magic missile, darkvision 60 ft.
Abilities: Str 6, Dex 28, Con 10, Int 13, Wis 17, Cha 13
Special Qualities: Invisibility, absorb energy, reflect magic missiles, immune to mental influence, silence, SR 15
Feats: Alertness; Lightning Reflexes; Weapon Finesse
Skills: Diplomacy +9, Knowledge (arcana) +7, Listen +11, Sense Motive +9, and Spot +11
Advancement: -
Climate/Terrain: Any land
Organization: Solitary
Treasure/Possessions: None

Source: Monster Compendium: Monsters of Faerûn

Magic Missile (Su): Every other round, a nyth can fire a single magic missile (as the spell), dealing 1d4+1 points of damage to any creature within 110 feet.

Invisibility (Su): At will, a nyth can blank out its radiance entirely (for 2d4 rounds at a time) in order to steal away from an encounter or approach its prey; during this time, it is invisible. A nyth that fires a magic missile pulses brightly appearing and remaining visible until its next action.

Absorb Energy (Su): Nyths ate not harmed by fire or lightning; in fact, they gain hit points from these energy forms. A nyth struck by a fire or lightning attack gains as many hit points as the attack would normally inflict. In combat, nyths have been known to fly into torches in order gain the benefit of healing (1 hit point each time).

When a nyth exceeds 60 hit points, it fissures into two smaller nyths, a process that creates explosive bursts of light and discharges of magic missiles in random directions (all living creatures within 30 feet are struck by 1d3 missiles each). The result is two nyths of average size (30 hp each).

Reflect Magic Missiles (Su): Nyths reflect magic missile spells aimed at them, directing them back at the caster.

Immune to Mental Influence (Ex): The strange minds of the nyths have proven impervious to all charms, compulsions, phantasms, and morale effects.

Silence (Ex): Nyths make no sound unless they speak. They cannot be heard with Listen checks unless they want to be.

Nyths bite prey that they can hit (often hiding with the sun behind them), but their major weapon is their magic missile attack.