Amorphous Form. The Aberrant Companion is shapeless. Allowing it to assume any shape it needs to survive. 

Magical attacks: The Aberrant companions attacks count as magical attacks.

Large form: Aberrant companion takes a large form that can be used as a mount.

Medium Form: The aberrant companion takes a medium form.

Small form: The aberrant companion takes a small form. Ideal for infiltration and stealth.

Multiattack. The aberrant companion makes two attacks in accordance to its form.

Large form:

 Weird Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.

Weird Spear. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 7 (1d6+ 4) piercing damage.

Medium Form:

Vacuous Slash. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 9 (1d10 + 4) slashing damage.

Vacuous Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 9 (1d10 + 4) slashing damage.

Small form:

Chittering Bites. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 9 (2d4 + 4) piercing damage.