Fungus gnat larva and pupal cases (likely)

Moist potting soil, decaying plant material, greenhouses, and damp indoor environments.

Larvae feed mainly on fungi, algae, and decaying organic matter, but may damage tender roots. Adults primarily consume liquids or do not feed substantially.

Larvae live in moist soil and pupate near the surface; adults emerge as small, dark, weak-flying gnats attracted to light. The image is not detailed enough for confident species-level identification.

Usually a minor nuisance, though abundant larvae can weaken seedlings and houseplants. They also help decompose organic material and serve as prey for other organisms.