User blog comment:Dremora archer/YO!/@comment-1647904-20091028131357/@comment-2081141-20101209071105

Actually the burden image is used for effects with no catagory. It's actually a 'Jyggalag's Voice' spell, it's just that there is no image for Jyggalag's Voice, so they use burden. Same for Summon Haskill, and the effect on the Languorwine Blade.