Hickory and I scampered across a bed of mulch–as squirrels always do in suburban yards–and were brought up short by this weird growth.
The ‘sunshine’ shape led me directly to identifying these as earthstar fungus. Their centers haven’t opened, but when they finish bulging out, dust-like spores will burst out of them. I had the worst time stopping Hickory from going back and smashing his paw into one to see if would spurt now. Can you imagine the mess?