Well I was watching Higrashi on youtube. And there was this one part where Rika beats up Satoko. Then I saw the related videos.
I saw Elfen Lied Puppy Dies
Cruel Death
So I watched it. These three boys find a girl named Lucy with a dog. Then one of them hold her so she doesn't get the dog and run away with it. She kicks the other boy and the boy says to beat the dog up. The other boy kicks the dog into the wall. The boy who said to beat up the dog gets a vase empties the vase and beats the dog. Her friend goes into the room and says sorry I told the boys about the dog! Then Lucy says "who know who are the humans? PEOPLE LIKE YOU!!! Then kills the boys in the room.
NOW that's epic. Blood everywhere in the room. How it was made. Oh boy that's cool. XD
So that's how I discovered it.