I’m 95% sure this slug was just moving across the dead twice-stabbed stink bug, not out to scavenge it, but I sure was confused when I came across the bizarre scene in the first photo. The slug moved on, leaving the bug slimily glued to the geranium leaf. I guess I’ve noticed in the past that slugs move in straight lines without much caring what they’re going over, and this seems to be a great example…
Slugs are often scavengers, so it wouldn’t be unusual if it was eating the dead bug.
Yeah, they famously eat all sorts of detritus and rotting things. But a) isn’t insect cuticle a little more solid than most things they eat, and b) it seemed to pass by without doing much to the bug. Maybe it scented something dead but decided there was no satisfactory meal to be had?
I think it would be eating the soft tissue inside the cuticle if it was eating anything. But I wouldn’t be that surprised if it just crawled over it.