The bubotuber is a plant that resembles a large black slug from above ground. This visible part also squirms of its own volition. The bubotuber is also covered in boils that produce a thick green pus when squeezed. This pus referred to as bubotuber pus, is described as putrid green and a stench of petroleum. Bubotuber pus is used to treat serve Acne but undiluted it has horrific effects on unprotected skin. (As Hermione learnt after receiving a letter containing raw bubotuber pus from Rita Skeeta)
1st years had the task of milking pus from the bubotubers, they were required to wear dragon hide gloves to protect them from the pus.
Some bubotubers grow to monsterous size, resembling giant green slugs. The giant breed is highly territorial and will squirt a jet of highly viscous pus at any life form that intrudes on their territory. This extremely sticky substance can stop a child in their tracks and glue them to the spot with ease.