Pounce.

If the Abyssal Hyenid moves at least 20 ft. straight toward a target and then hits it with a Bite attack on the same turn, the target takes an extra 5 (2d4) slashing damage. If the target is a creature, it must succeed on a DC 15 Strength saving throw or be knocked prone. If the target is prone, the Astral Hyenid can make another Bite attack against it as a bonus action.

Rampage.

When the Abyssal Hyenid reduces a creature to 0 hit points with a melee attack on its turn, the Abyssal Hyenid can take a bonus action to move up to half its speed and make a Claw attack.

Standing Leap.

The Abyssal Hyenid's long jump is up to 20 ft. and its high jump is up to 20 ft., with or without a running start.

Tunneler.

The Abyssal Hyenid can burrow through solid rock at half its burrow speed and leaves a 3-foot-diameter tunnel in its wake.

Multiattack.

The Abyssal Hyenid makes three attacks per round (Bite/Claw/Claw)

Bite.

Melee Weapon Attack: +6 reach 5 ft Hit: (1d10 + 4) slashing damage.