Skeleton horses spawned with an egg can be ridden, but are very hard to control at times.

I've been told these horses are not supposed to be tamable, but I can ride them after spawning them. I can't put saddles on them. When opening the inventory, it just opens the player inventory and shows the player sitting down in the armor preview. I wouldn't report it as a problem if it weren't for the fact that occasionally, my horse will stop turning where I point the camera and will keep running in a tiny figure 8 when I press the forward button until I get off of it and lead it somewhere else.