It's naturally fluorescent.
According to scientists in Brazil and Argentina , the little critter produces a certain pigment that, when hit with black light, changes to a bright neon glow.
Fluorescence is known about in various marine creatures - such as sharks and turtles - but we've never seen it on a frog before. It's not the same thing as bioluminescence which occurs when a creature generates light through a chemical process.
Instead, the frog's skin can absorb short wavelength light and reflect it as longer wavelength light.
The illuminating results were published in the in the journal Proceedings of the National Academy of Sciences this week.
These findings open an exciting perspective into frog visual physiology and ecology and into the role of fluorescence in terrestrial environments, where classically it has been considered irrelevant," wrote the authors.
The team says it is still studying why the frog glows - but suggest it could be to make it easier to spot for other frogs.
They also plan to look at other tree frogs in the same area to see if there are any other fluorescent species hanging around.
According to mirror.co.uk