I appear to have reached a truce with this group of wrigglers as they are just standing there with no animation. I have no clue what caused them to get into this state, but they die just fine, and if I leave it long enough more will join them.

The "tiny" seems to be constant pixel size, as it's less bad on my lower resolution monitor. The screenshot was taken on a 4k display. Problem goes away when switching back to X11.

I believe this to be related to a Steam update which messed up the cursor in a similar way, and swapping to 2.0.14 ...