Recently in an NBC News report, scientist Noriko Iwai of the University of Tokyo had discovered that the extremely endangered Otton frog has a nasty surprise tucked away in its “thumb”: a spiny dagger! Used for fastening itself to a mate (okay, ow), fighting off rival males, and holding up other critters for their wallets, the Otton frog’s thumb dagger is the sole reason you wouldn’t want to get all up in its face... like these five other animals that are packing hidden spines, poison, and other secret weapons to ruin your day!
