This is a pen and ink and colored pencil drawing of a Vietnamese mossy frog (Theloderma corticale). I saw these at the Toledo Zoo awhile back and was fascinated by their bumpy, mottled appearance. They blend right in with the moss and rocks in their habitat. On one hand, it was rather difficult to render, but on the other, very fun to just let the pen squiggle around all of the irregular shapes and patterns.
Vietnamese mossy frog (Theloderma corticale) – pen and ink and colored pencil