6. Poison Dart Frog
They look surprisingly beautiful and charming for frogs, but this is the case where appearance is deceptive. There are a few types of poison frog and the level of toxicities varies. They can be yellow, copper green, red, blue and black, but the most dangerous kind is golden. It can easily kill 10 adults if they touch it. So keep this rule in mind: in wild nature, the brightest colors are the most dangerous ones.