A blister beetle is a type of beetle known for its unique defense mechanism of secreting a toxic substance called cantharidin, which can cause blisters and skin irritation. They are typically elongated in shape, with vibrant colors and a hardened exoskeleton. Blister beetles are often found in fields and gardens, feeding on plants and sometimes acting as pests. Despite their potential harm to humans and livestock, they play a role in the ecosystem by preying on other insects.