Beetle, Water

Family: Beetles

Medium beast, unaligned

Armor Class 13 (natural armor)
Hit Points 37 (5d8 + 15)
Speed 20 ft., swim 60 ft.

15 (+2) 13 (+1) 16 (+3) 2 (-4) 10 (+0) 9 (-1)

Senses blindsight 60 ft., passive Perception 10
Challenge 1/2 (100 XP)

Special Traits

  • Water Breathing. Giant water beetles can only breathe water but can hold their breath for up to 8 hours out of water.


  • Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (1d8 + 2) piercing damage.
  • Ink Cloud (Recharge 6). A 10-foot radius cloud of ink extends all around the water beetle if it is underwater. The area is heavily obscured for 1 minute although a significant current can disperse the ink.


This giant beetle has a cylindrical and hydrodynamic body that tapers to a pointed tail section. Its wing casings and carapace are brownish black, and its legs are dull yellow. A silver stripe runs lengthwise along its back.

These highly aggressive beetles make their home in deep fresh water such as slow-moving rivers, lakes, large pools, and inland seas. They can be found in any climate, from the warmest to the coldest. Giant water beetles are predators. They sustain themselves on fish and other aquatic animals. They spend most of their lives in the water, rarely emerging onto land. In the rare cases when they are encountered on land, a giant water beetle is seldom more than 30 feet from water. They are diurnal creatures, hunting during the day and sleeping in deep water at night. They dive with blinding speed when they spot a potential meal in the water. When not actively hunting, they sometimes simply drift along with the current.

The giant water beetle normally uses its ink to escape from attackers, but thanks to its tremorsense, it can fight inside the ink cloud without penalty.

Giant water beetles lair on the bottoms of lakes, rivers, and inland seas.

A colony always contains at least one female and 2d4 eggs. Eggs hatch within three weeks after the female deposits them and reach full maturity in six to eight weeks.

When hunting, these creatures prefer to attack by ambushing their prey. They usually drift near the water surface and dive down onto targets below them with surprising speed, but they have also been known to drift in darker water at greater depth and lunge upward to seize prey with their tough, sharp mandibles.

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

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