Probably one of the fungi often called; "Devil's Snuff Box'
There are several Genera with that common name. Below is the CalPhotos site with photos of most of the fungi found in the state. You can browse though them to see if a positive ID is possible. (click on the previous & next links at top & bottom of pages to navigate entire site).

They can be removed, but if they have turned brown, there are millions of brown dust-like spores inside (hence the common name) and IMO it probably would be unhealthy to inhale them. They will eventually split open to release the spores, which are then dispersed by the wind. I had them appear in my lawn once and they persisted for a few years and finally disappeared. I didn't apply any chemicals or attempt to remove them.

Here is a link that might be useful: CalPhotos-Fungi by Common Name