Well, I just did something that I swore I'd never do... I tapped on the vile to get the spider to move. The good news is, it's not a deathcurl. The bad news is I have a super stressed GBB sling... I guess the mods can delete this thread if they like.
GBB slings are a bit nervous and stressed but usually they also calm down pretty quick. If they sort of touch their knees above the carapace it's not a deathcurl. Deathcurl is the legs under the spider.