A fable, from Aesop
A mouse and a frog became friends. Now the mouse lived entirely on land, while the frog, being an amphibian, was equally at home
on land or in the water.
"Mouse, you are my best friend forever," said the frog, and as a token of their friendship, and in order that they might never be separated, the frog tied himself and the mouse together by the leg with a piece of thread. This was fine while they went about on dry land, but then the frog spied a pond and jumped in. Frog began swimming about and croaking with pleasure.
Mouse, however, who was still tied to frog's leg, drowned, and floated about on the surface in the wake of the frog. High above the pond, hawk spied the dead mouse on the pond's surface. Hawk swooped down and seized the mouse in his talons, and, as a bonus, got a frog for a snack.
Harm hatch, harm catch.
(George Fyler Townsend, 1887)
For he that thynketh euylle ageynst good
the euylle whiche he thynketh shall ones falle vpon hym self.
(William Caxton, 1484)
Cross the river in a crowd and the crocodile won’t eat you. Well... not all of you.
Keep your friends close, but stay away from frogs. They're idiots.