The pools sparkle as the sun finally shoulders its way through the February murk. Beneath the surface, the seaweeds are sprouting up, the first sign of spring in the rock pools, and with them come the sea slugs. Many of these minute molluscs choose to spawn in the shallow waters around the shore, where their favourite foods such as sponges, sea squirts and seaweeds are abundant.

How they travel such distances to find mates and lay their eggs here is something of a mystery to me. They are delicate, squishy little things at best, and mere blobs of jelly out of the water. Once in the water, though, they reveal their colours and shapes, and most rockpoolers delight in finding them. Today, I see mostly pale, blobby ones rather than their spectacular cousins, but they are intriguing nonetheless.

I have ventured down a rocky gully that’s rarely accessible due to the pounding waves that surge through it. The overhangs are studded with Scarlet and gold cup corals, pinpricks of the brightest orange. Up close, I admire their translucent tentacles, wedging my head into the rocks to secure a better look.

Today, the unusual wind direction is keeping the waves at bay – just. The swell bubbles through a channel at my feet and every now and then spray is flung across the rocks onto my back. Places like this make me nervous and I’m constantly checking over my shoulder, expecting to be swept off into the Atlantic. As always, I forget all this as soon as I see an interesting creature.

In a hole under a rocky ledge beside a long pool is a white spiral of jelly. These are sea slug eggs and I know whatever laid them must be close by. After a minute of searching, I spot a blob on the rock and, taking great care not to squash it, I take it in my hand and pop it in a tub of water.

Before my eyes, the blob starts to unfurl. Its body takes on a more definite form and feathery antennae (rhinophores) extend from its forehead, while a frilled ruff of gills fans out of its back. Although it’s hardly the most colourful of the sea slugs, its creamy-white body has a pearly quality and its undulating sides make it look like it’s wearing layers of petticoats under its mantle. I am so absorbed in watching it I almost don’t notice the movement in my peripheral vision.

When I do look up, I almost slip off the rock in surprise. Emerging in a slow glide from its cave at the back of the pool are two vast black claws, followed by legs of a striking blue. Long red antennae are stroking the surface of the pool and I find myself staring into the eyes of a fully-grown lobster.

I’m sure you know as well as I do that lobsters don’t eat wellies, but when you’re on your own in a remote spot and one’s marching determinedly towards your toes, you start to question these things.

As your intrepid reporter from the Cornish rock pools, I know I mustn’t snatch my welly out of the pool, where it is dangling in front of those strong claws. Instead, I lower the container holding the sea slug onto the rock, flick my camera off the macro setting and start taking photos. I even manage a short video while the lobster, deciding that my boot doesn’t look tasty after all, backs into its hole and is soon lost from sight.

Moments like this take my breath away as only a close encounter with the natural world can. I remain staring into the pool for some time, a window into another world, until the rumbling waves remind me that it isn’t safe to linger here. Soon the tide will cover this pool and all its secrets once more.

Note: I have deliberately avoided specifying my location this week to keep Bob the lobster safe from harm!