Fungus?

Fungus?

Observation - Fungus? - UK and Ireland. Description: About 30cm in diameter and apparently attached to the log roll pictured. Looked almost polystyrene in appearance and very white although its outer surface appeared to have been eaten by slugs and snails. It appeared almost overnight much to the puzzlem

About 30cm in diameter and apparently attached to the log roll pictured. Looked almost polystyrene in appearance and very white although its outer surface appeared to have been eaten by slugs and snails. It appeared almost overnight much to the puzzlement of the garden owner.