Having an enchanted sword can kill a horse while riding it ..
How that bug was found: I was playing normal survival when I had to Enchant my diamond sword with fire aspect 1,I rided my horse and I was so exited to test it on the animals when I ACUALY realized i was not hitting the animals , but instead I was accidentally hitting my own horse , I was so frustrated about it i tried riding another horse and killing him with unEnchanted sword but I was not able to !? Steps to preduse :
1-saddle a horse or (tame) it
2-enchant a sword
3-ride the horse
4-look down or try hitting something with it
Horse will die due to that action
(Put in mind) : I've just tried the fire aspect enchanting i haven't tested them all