Veined tree frog
This frog makes a sticky white substance in its skin.  This substance has chemicals that can cause human beings' skin and eyes to hurt.  One of its names "pepper tree frog," comes from the idea that it makes people sneeze, like pepper does.  If a snake or other predator tries to eat the frog, it will make this white substance come out of its skin.  This will hurt the predator's mouth so the frog can hop away.  Because this substance does not dissolve in water, like wax does not, scientists also think it might also stop the frog from drying out and dying.