Monsters by Jack: Colossal Cave Crocodile

Just a few minutes ago I was out in my yard digging a hole for a tree I bought. And I was thinking two things:

  1. Digging holes in the middle of the Oklahoma summer sucks.
  2. I need to come up with a cool monster for the large pool in Dyson Logos’ Mushroom Cavern.

Fortunately, Jack, my six-year old, was about 5 feet from me (within D&D reach, mind you) spraying himself with a hose and screaming like a banshee (Con check 13 or drop to zero hit points).

“Jack!” I said. “I need help with a monster idea.”

I explained the situation to him, that there was a big cave with a big pool and inside it lived a big monster.

He seemed perplexed. Jack was used to coming up with random monsters from cartoons he’d watch. No one had ever asked him to come up with a monster based on instructions. Thus, it took a little leading to get him to come up with something.

“What type of creature lives in both water and land?” I asked.

“A crocodile!”


After finishing my holes, I came inside and looked up the giant crocodile listing in the Monster Manual. Challenge Rating 5, pretty tough critter. But the Mugmug had to be a serious threat. The giant croc was already Huge size, so I had to go one size bigger: Gargantuan.

Thus, the colossal cave crocodile was born.

Statting the Colossal Cave Croc

When you’re making a monster in D&D, the easiest thing to do is take a preexisting monster and adjust it. And that’s all I had to do with this guy. What really helps is that the giant crocodile has a regular crocodile to compare it to in the Monster Manual. By taking the deltas between their two stat blocks, I already have a built in template for decreasing or increasing the size of the crocodile.

Here’s another tip for increasing or decreasing monster sizes. Compare their abilities and actions to other comparable baddies. For example, if I give my colossal cave croc a Strength of 27, it will be as stronger than ancient white dragon; is that what I want?

Let’s dig in.

First, he needed higher stats and bigger attacks. Gargantuan creatures have crazy high Strength and Constitution, but tend to be a bit slower than their smaller counterparts. They’ve got marginally better movement, and their mental abilities tend to stay the same. For the croc, though, I thought it might make more sense that its a little wiser than it smaller cousins. When you’re that big, you’ve got to know when to hold and know when to fold.

Since this is a subterranean creature, I felt it was appropriate to give it darkvision and camouflage for hiding in its environment. With a naturally high stealth skill and camouflage, the colossal cave croc is a fearsome creature for sure.

I didn’t want to go too high on its challenge rating, so I bumped up its CR from 5 to 10. With its natural advantages (especially if there’s a pool of water nearby), it’d be a formidable foe for most second tier groups of adventurers.



Colossal Cave Crocodile

Gargantuan beast, unaligned

Armor Class 16 (natural armor)

Hit Points 155 (10d20 + 50)

Speed 40 ft., swim 60 ft.

Abilities Str 26 (+8), Dex 7 (-2), Con 21 (+5), Int 2 (-4), Wis 12 (+1), Cha 9 (-1)

Skills Stealth +6

Senses darkvision 60 ft., passive Perception 11


Challenge 10 (5,900)

Hold Breath. The crocodile can hold its breath for 30 minutes.

Underwater Camouflage. The colossal cave crocodile has advantage on Dexterity (Stealth) checks made while underwater.


Multiattack. The crocodile makes two attacks: one with its bite and one with its tail.

Bite. Melee Weapon Attack: +12, reach 10 ft., one target. Hit: 35 (5d10 + 8) piercing damage, and the target is grappled (escape DC 18). Until this grapple ends, the target is restrained, and the crocodile can’t bite another target.

Tail. Melee Weapon Attack: +12 to hit, reach 15 ft., one target not grappled by the crocodile. Hit: 23 (3d8 + 8) bludgeoning damage. If the target is a creature, it must succeed on a DC 18 Strength saving throw or be knocked prone.


Thanks for reading!

Hopefully you enjoyed Jack’s monster, the colossal cave crocodile. Be sure to keep checking each day for more cool 5e monsters and maps from me and Jack.

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See you then!

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