Slime mould
Myxogastria: syncytial or plasmodial slime moulds, the most commonly encountered. A common slime mould which forms tiny brown tufts on rotting logs is Stemonitis. Another form which lives in rotting logs and is often used in research is Physarum polycephalum. In logs it has the appearance of a slimy web-work of yellow threads, up to a few feet in size. Fuligo forms yellow crusts in mulch.