The slug/worm for me looks like this, rather than your reference image:

This is on openSUSE Tubmleweed, using NVIDIA drivers (375.20) on QupZilla. The variant and the original look completely the same.

It’s pretty great how the shape of the thing is completely different across different vendors. Is there any reference anywhere about how it’s supposed to look like?

Also, Medium doesn’t allow posting comments on QupZilla, so I had to switch to Chromium (which renders the image the same way, as both are based on Chromium) to post this. Pretty great how user agent sniffing is still used to detrimental effect in 2016.