Monkey Slug (caterpillar of the Hag Moth)

Deciduous forests, woodlands, and suburban areas where host trees are present.

Leaves of various deciduous trees and shrubs, including apple, oak, birch, cherry, ash, and chestnut.

The larva moves in a creeping, slug-like manner, using its bizarre, curved fleshy arms which it can detach if threatened. When fully grown, it spins a hard, spherical, brown cocoon attached to twigs or bark.

The stinging hairs on the caterpillar can cause skin irritation, itching, or allergic reactions in humans upon contact. As part of the ecosystem, they are minor herbivores of various trees and serve as prey for insectivorous birds and parasitic wasps.