I love things like this in Skyrim; these random, unscripted battles!
Last night I had a mini-quest which involved killing a (blood) dragon, and as the fight started I saw frost attacks flying up from a nearby hill. Went over to join the fun, and pretty soon there were 2 vampires, a Blood dragon, an Elder dragon, myself - oh, and my horse, all involved.
(The sad news was my horse was killed, just as I was completely overburdened with dragon bones/scales. Too stubborn to leave any behind, I walked - overburdened - from Dragontooth Crater all the way to Markath. Damn you, ex-horsey!)
You know the trick on how to turn your follower into a pack mule? Forgive me if you are the one who told me about it, lol.
I'm running into issues with Lydia dieing on me in combat. As previously mentioned a couple times when I accidentally hit her with a shout. But I've got to figure out what level she is (know how to do that?), maybe do the turn-her-loose and then have her rejoin me to reset her level?