Stone Build. The abyssal elephant is immune to the prone condition and can't be moved by the telekinesis spell, but do to it's stone like armor it is unable to swim.

Iron Gut. The abyssal elephant is immune to any type of poison and can ingest almost anything.

Charge. If the abyssal elephant moves at least 20 feet straight toward a target and then hits it with a horn attack on the same turn, the target takes an extra 18 (4d8) piercing damage. If the target is a creature, it must succeed on a DC 14 Strength saving throw or be pushed up to 15 feet away and knocked prone.

Siege Monster. The abyssal elephant deals double damage to objects and structures.

Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 19 (4d6 + 5) piercing damage.

Horn. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 14 (2d8 + 5) piercing damage.

Hooves (only if a creature is behind). Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 15 (4d4 + 5) bludgeoning damage.

Hooves Retaliation. If a creature passes by, behind the abyssal elephant, it can use it's reaction to make a hooves attack. The creature must succeed on a DC 14 Strength saving throw or be pushed up to 30 feet away and knocked prone.