The so-called 'cocaine hippos' of deceased drug lord Pablo Escobar attacked a man out fishing, leaving him in hospital with devastating injuries.
Before being shot dead in December 1993, Escobar illegally bought four hippos to live at his Hacienda Napoles estate in north-west Colombia.
The five hippos have now become a family of around 80.
One man was out fishing with his son on October 31 when they were attacked.
It is believed they were attacked because a mother was protecting her young calf.
The incident marks the second 'cocaine hippo' attack in the area this year.
Jhon Aristides Saldarriaga Marquez, 31, was fishing at a lake in the village of Napoles with two friends and his son when the hippo attacked.
He said: "The animal came after me, it hit me in the eye.
"I backed away and managed to run a bit, but I tripped and the hippo attacked me. I think it had a baby with it."
Tulio Hernan Ramirez, director of the San Esteban de Puerto Triunfo Health Cooperative, said: "The victim had several injuries to his left arm, the left side of his chest, as well as a blow to the head."
Escobar bought four two-tonne hippos - one male and three females - from a Californian zoo in the early 1980s.
Whilst many of Escobar’s other animals were captured and relocated after his death, the hippos were too difficult to find and have continued to increase in number.
They were allowed to stay on the land but soon escaped to an area around the Magdalena River.
Jorge Caro Lopez, a vet at Hacienda Napoles, now a theme park, said their growth cannot be controlled and they already inhabit various areas, making it dangerous for people to go.
The attack comes as the 'cocaine hippos' were ruled by a US court to legally be considered people.
The move saved them from being culled by Colombian authorities and has made them the first non-human species to be recognised as “interested persons”.
The District Court for the Southern District of Ohio recognised the animals as legal persons for the first time in US history on 15th October.
On behalf of the hippos, the Animal Legal Defense Fund filed an application in Colombia on the same day in an attempt to prevent them from culling the animals.
