Larva under water, it has a orange head with dark red pincers, and brown caterpillar like body, which is wrapped around a brown spire shell of a water snail which has little blobs of green algae on. All resting on a few strands of green pond weed
One thing on my list to film is this behaviour I witnessed a few years ago now.
Its a Great Silver Water Beetle larva eating a snail. It grabs the water snail with its asymmetrical mouthparts, wraps its body around it and uses brute force to crunch through the shell and get the soft chewy centre!