I used to have a large Maine Coon cat. I went to bed drunk and closed the door. Little did I know, the cat was in the room and I locked him inside with me. There was no litter box in the room. I woke up in the middle of the night on my back. I put my hand on my chest and felt something weird. Then the smell hit me. He had taken a HUGE soft serve style shit on my chest. Threw the comforter in the corner and went back to sleep. TL;DR: My cat gave me a spiteful soft serve cleveland steamer for locking him in my bedroom.
ComeOnYou

I have two cats, and if I am taking a bath, they will try to push each other into the filled bath tub. Anytime one is walking along the edge of the tub, the other will wait until they are walking inside the shower curtain, and then pounce with a full-force shove pushing them into the bath water.
Vacwming

My cat absolutely hated my sister — not full blown hissing and attacking, but on a psychological level of hate that I’ve never thought a cat would have.
My sister had this asshole of a Budgie that attacked him (they were both young, bird was hand reared) and my cat realise who owned it and decided to exact revenge. He wasn’t young either, this was 5 years after the original incident.
He managed to get into the cage, kill the bird and hide it under my sisters sheets (fucks me how he did it) and, because she slept on a doona and then another blanket, she didn’t notice the rotting corpse of her beloved Tweeters.
She was cleaning up one day and noticed something didn’t smell right, my cat noticed the commotion, and so did I, so we went to investigate, there was the body of the bird, flat and rotted, underneath a blanket and a sheet.
My cat then jumped on the bed and coughed up a fur ball and strutted away.
He’s a fucking d*ck.
blackplague06

Stare right at me before knocking things over. Not especially bad, just a definite “I’m going to do this because I know you don’t want me to,” several times.
TentacledTessa

Image Credit: Imgur

The morning of my wedding, my big boy cat decided to leap off the headboard onto my face, claws exposed. He weighed 17 lbs. I had a huge deep scratch down my nose, which the photographer was able to edit out.
brock_lee

My girlfriend accidentally kneed me in the balls, then I rolled over and fell out of bed. Her cat jumped on my nuts about 3 seconds after I hit the ground.
Dick move Mushu…d*ck…move…
INS0MN14C

the cat we used to have would stand in the litter box, hang it’s ass over the side and shit on the floor.
Eagle1388