Well I clicked a horse with a chest because i thought all horses could have a chest put on them, but only muels can, then i kept on trying to ride it but the horses inventory opened repeatedly and i was un-able to get on the horse (it was also saddled) Later it got fixed when i reloaded mine craft.

Also later i got on the horse and when a skeleton attacked me, once the skeleton died my dogs attacked my horse but didn't damage it, they also made the aggresive sound.