A man in Italy is facing a year behind bars and over a $100,000 fine after cops busted him with a rare crocodile living in his bath tub.

The animal has been identified as a critically endangered Cuban crocodile, and while the potential cigar smoking croc is just a bub right now, experts say this breed is the most intelligent and aggressive out there and it would eventually grow to three metres in length.

Owner Fabio Lazelli’s bath-time buddy was discovered when neighbours dialled 999 (Italy’s 000) following an apartment block bust-up.

"They demanded to be let into his flat and were astounded when they found a crocodile swimming around in the bathtub," said one resident.

Lazelli is believed to have smuggled the croc into the country as an egg and leaving it to hatch at home.

One wildlife expert said: "He's very lucky we got it when we did. These crocodiles are the most intelligent of their kind, fast, and aggressive (piece of cake for late Steve Irwin). As it got older he would have been in real danger."