There was a common garden snail hidden in the tree trunk. From the Phyllum Mollusca, Class Gastropoda, which includes members such as slugs, octopus and squids etc, snails are a group of slowly moving or crawling invertebrates (without a background) with a calcareous shell and a slimy body that secretes a mucous like substance.
They are often unpalatable and distasteful and thus have few natural enemies or predators. Their most famous member on cuisines is the escargot, which is a dish of cooked land snails.
Links on snails are attached below for reference: