Epomis beetle larvae feeding on a froglet.

source - reddit

 

Epomis beetle larvae feeding on a shrub  (Pseudophilautus) froglet.

These ground beetle larvae feed exclusively on amphibians (frogs especially), they use prey-like movements and lure frogs to them by looking like an easy meal.

Once they are close enough, the beetle grabs and locks on to them using their sharp double jaw, which pierces deep into the frogs body.

Once its latched, it will liquefy and suck on the bodily fluids of its prey, reducing the frog to a pile of froggy bones. 

Sometimes, the frog succeeds in eating the epomis beetle larvae, but the victory is short lived as it will usually vomit the predator up and get attacked by it anyway.

It is one of the few instances of a former prey item evolving to prey on its former predator.

pic click by girishgowda.c