Cops found a nasty looking caiman in a Brooklyn living room they were searching for guns on Thursday morning.

Police were looking for drugs in a sixth-floor apartment at 21 E. 21st St. when they made the startling discovery at 6:20 a.m, cop said.

The caiman — a sub-species of crocodile — was living in a aquarium in the living room, officials said.

Building residents were shocked to hear about their toothy neighbor.

“I can’t believe it,” said Sandra Etienne, 38, who lives on the fifth floor. “I have never seen that alligator around before. If I saw it, I would be scared and would call the cops.”

But another neighbor said the reptile — which is not much larger than a brick, photos show — had a certain charm.

“That’s nothing to be scared of. It’s actually kind of cute,” building resident Jay Saunders said after seeing a picture of the creature.

Police also recovered a .380 semi-automatic handgun and crack cocaine. They charged resident Habakkuk Tracey with weapons possession, drug possession and possessing a “prohibited animal.”

The caiman was handed over to Animal Care and Control. The organization does not comment on critters in its care, but a spokeswoman said it typically transfers wild animals such as caimans to rescue groups on the same day it receives them.