stinkbug

Short definition from Wiktionary

Noun

1. 1
   Any of several insects, usually shield-shaped, possessing a gland that produces a foul-smelling liquid, usually containing aldehydes, which they use to discourage predators.
2. 2
   Any of various insects of the order Hemiptera (the "true bugs"), in the suborder Heteroptera, principally in the superfamily Pentatomoidea or Coreoidea.
3. 3
   A pinacate beetle or stink beetle (genus Eleodes) that releases a pungent odor when threatened.