I never knew that, until I tried.

I use lighting mod, and sometimes the night is very dark. At this time, even a dang dragon is hard to see.

So, I shot a Magelight at it, and it sticks.
This also works with people, and I assume it will also work with creatures.

When it sticks at actors, it is counted as a separate edition of Magelight that sticks on worldspace, and works as if that actor casted Candlelight. This means that you can at most have 2 Magelights, one that sticks on actors, one that sticks on the area.

It's the literal mark of "kick me".