Rio de Janeiro’s iconic carnival might transform into a croccy horror show as alligators invaded the Brazilian metropolis.

The four-day festival, which begins on Wednesday and is attended by two million revellers everyday, will include up to 5,000 uninvited visitors.

According to conservationists, caimans – alligator-like reptiles that can grow up to 13ft long and weigh up to 12st – are residing in rivers and lagoons across the beach city and have begun to emerge from drains.

They’ve been seen walking around streets, lazing in the sun, and even infiltrating homes.

Experts believe that urbanisation, contaminated ecosystems, and human feeding have all contributed to their increased prevalence.

“Rio has 5,000 caimans, and there’s a good possibility more than a few will turn up to the celebration,” one added. It will give the event a little zip.”

The story comes after a 12-foot alligator was discovered hanging out in the master bedroom of a freshly built house in Florida and was swiftly expelled.

The alligator was discovered by a worker fixing window blinds in the upscale neighbourhood of Babcock Ranch, where homes can sell for up to $1.5 million (£1.14 million).

After the sliding doors were temporarily removed, it took two experienced trappers to get the alligator out via a patio.

After numerous terrifying death rolls, three guys bring the beast into the front garden and load it into a car.

“The wind closed the door and he was stuck,” project manager Matthew Goodwin told McClatchy News. He entered every room and left his imprint.”

Another gator grabbed attention on March 23 as it laid in the centre of the road, stubbornly refusing to move out of the way of traffic in Florida.

Deputies from the Walton County Sheriff’s Office arrived to find cars backed up and a baby alligator laying on the road.

Finally, a shovel was used to drive the alligator off the road and into a neighbouring forested area. The alligator was plainly irritated, turning numerous times and snapping at the shovel.