Few instances where animals apparently held grudges against humans and retaliated are down below.

A Tiger Tracked Down and Killed the Poacher Who Shot It

https://www.npr.org

Getting on the nerves of an apex predator like a Tiger is a very bad idea and could have some seriously undesirable consequences.

Russian poacher Vladimir Markov found out the hard way after attacked one in the Russian Far East in 1997. Markov shot and wounded the tiger during a hunt, and to add insult to injury, he took part of its kill. The tiger didn’t forget, and between 12 and 48 hours later, it tracked Markov to the cabin where he lived. Markov wasn’t home, so the tiger destroyed anything in the cabin that had his scent and patiently waited for him to arrive. When Markov finally did, the tiger killed and ate him.

A Pack of Dogs Vandalized a Car Because the Owner Assaulted a Comrade

http://www.petspet.org

In 2015, a man in Chongqing, China, drove to his home one evening to find a stray dog lying in his parking space. Instead of shooing the dog, he proceeded to kick it out of the way before parking his car and entering his home.

The canine didn’t take the kicking incident lying down. It left but returned with more dogs, and they all proceeded to vandalize the man’s car. They used their jaws to make dents in the car and bit the windshield wipers. The man was shocked when he awoke the next morning to find his car full of dents.

Truman the Octopus Shot Streams of Water at Lady It Didn’t Like

https://orionmagazine.org

Truman, an octopus that used to live at the New England Aquarium in Boston, Massachusetts; took a particular dislike for a woman who was volunteering at the aquarium and would shoot a stream of water at her at every opportunity he got. The lady later left for college but returned for a visit few months later. Truman, who hadn’t been shooting water at anyone in the meantime, quickly shot a stream of water at her the moment he saw her.

Crows Recognized and Attacked Some Researchers for Capturing Them

https://www.toptene.com

Some researchers—who had been capturing and attaching identification bands on some crows—discovered that the birds kept grudges when they noticed that the crows made noises and swooped at them whenever they entered their territory.

To prove their theory, the researchers started wearing masks when capturing and tagging the birds. With time, they realized that the crows made noises whenever they saw the masked person around. The crows didn’t forget the faces and still recognized the masks even after they didn’t see them for a whole year.

An Angry Camel Bit Its Owner’s Head Off

https://www.indiatoday.in

In 2016 a man named Urjaram was killed by his own camel. Urjaram, had been engrossed in hosting some guests in his home in Mangta village, Rajasthan, India, that he forgot about the camel he tied out in the scorching sun for the whole day.

When Urjaram tried untying the camel at night, the already angry camel caught him by the neck and lifted him up before throwing him back to the ground. Thereafter, it chewed on the neck until the head was separated from the body. It took 25 villagers about six hours to calm the angry camel down.