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Huge beast, unaligned

Armor Class 15 (natural armor)
Hit Points 270 (20d12 + 140)
Speed 40 ft.

28 (+9) 10 (+0) 24 (+7) 2 (–4) 13 (+1) 6 (–2)

Senses passive Perception 11
Challenge 9 (5,000 XP)

Special Traits

  • Keen Smell. The mastodon has advantage on Wisdom (Perception) checks that rely on smell.
  • Trampling Charge. If the mastodon moves at least 20 feet straight towards a creature and then hits with a gore attack on the same turn, that creature must succeed on a DC 19 Strength check or be knocked prone. If the target is prone, the mastodon can make one stomp attack against it as a bonus action.


  • Gore. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 27 (4d8 + 9) piercing damage.
  • Stomp. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 48 (6d12 + 9) bludgeoning damage and the target must succeed on a DC 17 Constitution saving throw or be stunned until the end of the mammoth’s next turn.


This elephantine beast has a coat of thick fur and stands longer and lower to the ground than a typical pachyderm. Its tusks are long and curved, providing it with formidable natural weapons.

The great mastodon is a distant relative of the common elephant and is linked to that creature through the woolly mammoth. It is an herbivore and is found primarily in forested areas. Its teeth are rounded and pointed and make excellent “tools” for clipping leaves, branches, and twigs though its diet also includes things such as grasses, fruits, berries, and nuts. A typical mastodon consumes 400 pounds of food and 50 gallons of water each day. Mastodons generally deplete an area of its food supply before moving on, traveling in large herds with the young in the center, surrounded by the adults of the herd.

The mastodon does not have any particular season for reproducing, though most births seem to occur in the winter.

Young are born with short, thick fur and weigh around 240 pounds.

A young mastodon reaches maturity at about age ten.

The mastodon has three naturally occurring predators: the dire wolf, the smilodon, and man. The latter often hunts the great mastodon for its meat, fur, and the ivory of its tusks. Young mastodons are often captured alive and taken into captivity to be trained as mounts or beasts of burden.

The mastodon is a distant relative to the elephant though it is slightly longer and lower to the ground, with shorter and thicker legs than the common elephant. Its head is slightly longer and taller than an elephant’s and the mastodon’s entire body is covered in thick fur of brown, gray, reddish-brown, yellowish-brown, or black. Its long, upward curving tusks are formed of ivory and are white or yellowish-white in color. Its eyes range from gray to brown to green. An average mastodon stands 20 feet tall.

Mastodons are generally peaceful creatures and avoid combat. They have no natural fear of any creature, so they do not flee. If threatened or if their young are threatened, mastodons fight by goring with their tusks or trampling foes. Mastodons fight to the death to protect their young.

Training a Mastodon

A mastodon must be trained before it can bear a rider in combat. To be trained, a mastodon must have a friendly attitude toward the trainer. (This can be achieved through a successful Animal Handling check.) Training a friendly mastodon requires six weeks of work and another successful Animal Handling check (DC 20). Failure means that the beast is not fully trained and another 2 weeks of effort will be required to try the check again. Riding a mastodon requires an exotic saddle. A mastodon can fight while carrying a rider, but the rider cannot also attack unless he or she makes a successful Strength (Athletics) check. Mastodon young are worth 16,000 gp each on the open market. Professional trainers charge up to 2,500 gp to rear or train a mastodon.

Carrying Capacity. A mastadon is unencumbered up to 5,592 pounds; a lightly encumbered from 5,593 to 11,184 pounds; and encumbered from 11,185 to 16,800 pounds. A mastadon can drag 84,000 pounds.

Section 15: Copyright Notice

Tome of Horrors © 2018, Frog God Games, LLC; Authors: Kevin Baase, Erica Balsley, John “Pexx” Barnhouse, Christopher Bishop, Casey Christofferson, Jim Collura, Andrea Costantini, Jayson ‘Rocky’ Gardner, Zach Glazar, Meghan Greene, Scott Greene, Lance Hawvermale, Travis Hawvermale, Ian S. Johnston, Bill Kenower, Patrick Lawinger, Rhiannon Louve, Ian McGarty, Edwin Nagy, James Patterson, Nathan Paul, Patrick N. Pilgrim, Clark Peterson, Anthony Pryor, Greg Ragland, Robert Schwalb, G. Scott Swift, Greg A. Vaughan, and Bill Webb