Amazon Milk Frog aka Trachycephalus resinifictrix

The Amazon milk frog is sometimes referred to as the blue milk frog. These frogs are fairly large, reaching sizes of 2.5 to 4.0 in (6.4 to 10.2 cm) in length. Adult frogs are light grey in colour with brown or black banding, while juveniles will exhibit stronger contrasts. As they age, their skin develops a slightly bumpy texture. The "milk" in the common name comes from the milky fluid these frogs excrete when stressed.