6. Plague Beetles
Source: Iconosquare
These swarming beetles clump in the treetops causing the limbs to sag and break. Their swarms are so massive they have been known to blacken the sky and cause an overwhelming stench of decay. While they are not guilty of spreading the disease of their namesake, these strikingly beautiful beetles come in dazzling metallic colors. This is perhaps their way of getting your attention long enough for the sense of doom to set in.