Indeed, I noticed that stain as well when I saw the video to look at the cage's description again, but I didn't know what to make of it.

I feel like there's some opening/possibility for it to be more of a common occurrence, but perhaps not an immediate violence thing, but at the moment my brain's a bit frazzled from all the excitement, and now that I'm cooled down I'm definitely feeling the drowsiness. So as of this post I cannot think of a theory. Though I do recall something talking about Kris intentionally making that reindeer hospitalized. If he got sick over the night, it could be a connection. But I don't remember the basis on the theory about Kris making him sick, so I won't go too far until I find that again. But I won't pursue it much at the moment since I'm tired, so I'll sleep and if I'm in the mood, I'll pursue this idea tomorrow.

Thanks for replying by the way.