Big Sammir

Mimicry. The raven can mimic simple sounds it has heard, such as a person whispering, a baby crying, or an animal chittering. A creature that hears the sounds can tell they are imitations with a successful DC 15 Wisdom (Insight) check. Sammir can also mimic humanoid speech.

Flyby. The owl doesn't provoke opportunity attacks when it flies out of an enemy's reach.

Magical Weapons. Sammir's beak is a magical weapon. Whenever he attacks, a spectral, shimmering beak extends around it, dealing extra force damage on the attack. 

Innate Spellcasting. Sammir is a 5th-level spellcaster. Whenever the wizard changed him into a raven, he also imbued magic within him. His spellcasting ability is [Charisma] (spell save DC 18, +9 to hit with spell attacks). Sammir has following spells prepared:

Cantrips (at will): message, minor illusion
1 Level (4 slots): fog cloud, magic missile, shield
2 Level (4 slots): enlarge/reduce, suggestion
3 Level (4 slots): hypnotic pattern, lightning bolt

Multiattack.  It  makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 18 (2d6 + 7) piercing damage.

Claw. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 7) slashing damage.