|Ganoderma applanatum, "Artist's conk"|
Look, I don't make this stuff, I just find it
Here's another one
Six years after I posted this, I looked at it again, and now I think it's Ganoderma applanatum, an old one. The original post was "Fresh young polypore sculpture" and I had identified it as Ischnoderma resinosum. But now I don't remember where it was growing, and I don't have more details to refer to. I was overly eager, and fairly inexperienced. It's a phase many mushroom people go through. No shame.