The Frogfish is related to the Anglerfish. With his short, stocky body he has an atypical appearance fo ra fish, but it does permit him powerful camouflage. He relies on camouflage to both protect him from predation and also to ambush prey. If prey comes to rest near him, he will creep slowly forward, preparing himself for the lunge. His mouth opens to create a massive cavity and he engulfs the prey, literally sucking it in within about 6 milliseconds. He will happily devour anything up to twice his own size, and in captivity has been known to eat other frogfish, even potential mates.
Here he is in action: https://www.youtube.com/watch?v=qUNhQ-uF3T4