Ground beetle (likely a violet ground beetle)

Usually lives on the ground in gardens, woodland, and other sheltered, damp places; it may wander indoors.

Predatory; hunts slugs, snails, caterpillars, and other small invertebrates.

Mostly active at night and shelters under stones, logs, or debris by day. Adults are fast-running beetles and generally do not fly.

Harmless to people and beneficial in gardens because it eats common plant pests; it may release a defensive-smelling fluid if handled.