The hippopotamus is a CR 4 Large Beast from the 2024 rules (SRD 5.2.1) with AC 14, 82 hit points, Strength 21 and a Multiattack of two Bites at +7 for 16 (2d10 + 5) piercing each. That's 32 damage on a turn when both land, more than many level 4 characters have. It swims at 30 feet and can hold its breath for 10 minutes, so it fights from the water and retreats underneath it. SRD 5.1 has no hippopotamus, so there's no 2014 version to compare.
Large Beast, Unaligned
Offense and toughness are high: 82 HP, AC 14, a +7 Strength save. Everything else is poor: initiative −2, Dexterity 7, Intelligence 2, no darkvision. It hits like a CR 4 monster and thinks like a cow.
The damage is real. Against AC 16, a +7 Bite hits on a 9 or higher (60%), so two Bites average about 19 damage a round. A level 4 wizard with 22 HP can drop in one bad turn. Each Bite ranges from 7 to 25 on the dice roller.
It acts late. With initiative −2, the party usually goes first; the hippo makes up for it once it closes.
Water is its armor. On land, 30 feet of speed outruns no one. In murky water a submerged hippo is out of sight from the surface, and it can stay down for 10 minutes before it comes up beside whoever is wading or in a boat. Under the 2024 underwater rules, characters without a swim speed have disadvantage on melee weapon attacks unless the weapon deals piercing damage, ranged weapon attacks have disadvantage, and anything underwater has resistance to fire.
Play it as an animal. It defends its stretch of river. When the party leaves the water and backs off, it stops chasing; below about half HP, it sinks and stays down.
One hippo (1,100 XP) is a Moderate encounter for four level 4 characters under the 2024 rules (1,100 of the 1,500 Moderate budget). For four level 5 characters one hippo is Low, so use two (2,200 XP, Moderate), or a hippo plus a giant crocodile for a two-front river crossing: 2,900 XP, still Moderate (2,900 of the 3,000 Moderate budget).
For 2014 encounter math, our encounter calculator rates a single CR 4 creature as Medium for four level 4 characters.
Under the 2024 Polymorph, the form can be any Beast with a CR no higher than the target's level or CR, and the target gains Temporary Hit Points equal to the form's HP. A level 4 or higher ally turned into a hippo gets 82 Temporary Hit Points, two +7 Bites, a swim speed and a 10-minute breath hold, which makes it a strong pick for a river or lake fight.
The ford. The only shallow crossing for 20 miles runs through a hippo's wallow. The party can fight, wait for night when it grazes on the far bank, or distract it. The fight is optional; the river isn't.
Barge in trouble. A merchant barge is stuck on a sandbar and a hippo keeps ramming the hull. The town holds the hippo sacred, so the crew wants it driven off, not killed.
CR 4, worth 1,100 XP. It appears in the 2024 rules (SRD 5.2.1).
Not in SRD 5.1. The hippopotamus is a 2024 SRD 5.2.1 stat block.
Each Bite deals 16 (2d10 + 5) piercing damage, and it makes two per turn, so 32 on average when both hit.
10 minutes, from its Hold Breath trait.
Stat blocks: System Reference Document 5.2.1 (2024), Wizards of the Coast, CC-BY-4.0. Tactics, encounter math and ideas are Loreify's own.
This page includes material from the System Reference Document 5.1 and 5.2.1 by Wizards of the Coast LLC, available under the Creative Commons Attribution 4.0 International License. Loreify is not affiliated with Wizards of the Coast.
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