Giant Catfish (5e Creature)
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Large beast, unaligned
Hold Breath. While out of water, the catfish can hold its breath for 30 minutes.
Slippery. The catfish has advantage on ability checks and saving throws made to escape a grapple.
Water Breathing. The catfish can breathe only underwater.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) piercing damage, and the target is grappled (escape DC 14). Until this grapple ends, the target is restrained, and the catfish can't bite another target.
Swallow. The catfish makes one bite attack against a Medium or smaller target it is grappling. If the attack hits, the target is swallowed, and the grapple ends. The swallowed target is blinded and restrained, it has total cover against attacks and other effects outside the catfish, and it takes 5 (2d4) acid damage at the start of each of the catfish's turns. The catfish can have only one target swallowed at a time.
The giant catfish lurks in murky waters, slowly moving over the bottoms of rivers and lakes and sifting through them with its long and incredibly sensitive barbels. As soon as it detects something, it bites and tries to swallow its prey whole. Because they are primarily bottom-feeding scavengers and are quite sizeable, they are solitary and claim large territories, rarely gathering in groups.