Trampling Charge. If the mammoth moves at least 20 feet straight toward a creature and then hits it with a gore attack on the same turn, that target must succeed on a DC 18 Strength saving throw or be knocked prone. If the target is prone, the mammoth can make one stomp attack against it as a bonus action.

War Carriage. The mammoth carries a custom-made carriage that allows four Medium creatures or one Large creature to be transported on its the back. This carriage is attached to the creature by four leather straps and harnesses which, if severed, cause it to tumble off the creature’s back. Each of the straps of this war carriage are Tiny objects with AC 18 and 10 hp and immunity to poison and psychic damage.

Mounted Weaponry. The mammoth's carriage has four mounted harpoon crossbows attached to the railings of its war carriage. Any humanoid creature within the carriage can make an attack with this weapon as an action (see the mammoth's Actions).

Gore. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 25 (4d8 + 7) piercing damage.

Stomp. Melee Weapon Attack: +10 to hit, reach 5 ft., one prone creature. Hit: 29 (4d10 + 7) bludgeoning damage.

Mounted Harpoon Crossbow (Rider Only). Ranged Weapon Attack: +5 to hit, range 60 ft., one target. Hit: 5 (1d10) piercing damage and the target must succeed on a DC 13 Strength saving throw or be harpooned. A harpooned creature takes 3 (1d6) piercing damage at the start of each of its turns and can’t move more than 60 feet from the war monster. If a creature on the war platform succeeds on a Strength contest against the target as an action, it can move the target up to 30 feet closer to the platform. The creature can repeat this saving throw as an action, ending the effect on a success.