There is a real world animal that does this simply and efficiently as possible. The Alligator Snapping Turtle use it's tongue to imitate a wriggling pink worm that lures fish into striking distance of the predator. No prior food required (although this is not the only method of procuring food the the Alligator Snapping Turtle as it will eat carrion and has been known to eat American Alligators. Additionally, your creature has features that would make it ideal to take a similar strategy to the Mimic Octopus, which has been observed to mimic a wide variety of sea life both in defensive and aggressive situations.
Aggressive Mimicry is a strategy employed by any animal who adapts to luring prey by imitating a situation that entices its prey, while defensive mimicry is a strategy where imitating dangerous non-prey deters predators (such as some species of non-venomous snakes and butterflies which have colors that are similar to venomous snakes and butterflies. One famous example is that of the Coral Snake. It's distinct Red-Yellow-Black bands are imitated by two separate non-venomous species of snakes, both the Scarlet King Snake and several subspecies of the Milk Snake, which share a Red-Black-Yellow. Those living in the Eastern United States, the home of these snakes, have a several poems to help remember which ones are safe and which are not (Red on Yellow, Kill a Fellow. Redo on Black, Venom Lack/Friend of Jack). Other Milk Snake sub-species have been killed by humans who mistake them for other venomous snakes, such as Pygmy Rattle Snakes or Copperheads, also found in these similar ranges in North America.
