My PCs recently derailed a whole bunch of my planning through creative play – which is fine, the surprises make the game more entertaining for me this way – they ended up in the Slumbering Ursine Dunes and here are converted monsters for my own reference with abbreviated 5e stat blocks.

Though colloquially called “zombastodons” by feckless wags who care not for life and limb, the Mammut Morbidium is a reanimated spirit-demon of the more mundane mastodon.


Huge undead, chaotic evil
AC 13, HP 126, Speed 40′
Saves +4, +0, -4
Damage Immunities Poison
Condition Immunities Poisoned

Challenge 6 (2,300 XP)

Trampling Charge. If the zombastodon 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 zombastodon can make one stomp attack against it as a bonus action.

Undead Fortitude. If damage reduces the zombastodon to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the zombastodon drops to 1 hit point instead.

Roll randomly each round:
  1. Gore. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 4d8 piercing damage.
  2. Stomp. Melee Weapon Attack: +10 to hit, reach 5 ft., one prone creature. Hit: 4d10 bludgeoning damage.