The botrax is found in some medieval encyclopedias. It is a serpent with the face of a frog. It has a stone on its forehead that is used as a remedy against poison. It likes to live in wet places. It can be defeated by the spider, which bites it and causes it to swell.

It is possible that the names botrax (also called borax) and buffones both refer to the frog or toad (bufo), which is said to have a stone in its forehead called the toadstone, which Thomas of Cantimpré says is called crapadina in French. This stone is a remedy against poison. Thomas of Cantimprésays the botrax prefers wet place, and also says it is a species of buffones. Bartholomaeus Anglicus clearly says the botrax is a kind of venomous frog or toad. These correspondences suggest that buffones and botrax refer to toads or frogs, but this is uncertain.

The botrax has a stone on its forehead that is used as a cure for internal ailments and is also a remedy for poisons. There are two kinds of stones, one white and the other brown with a blue "eye" in the middle. The white ones are better.