The ruby-tailed wasp is a beautiful creature but it's not very nice.

Wikipedia - ruby-tailed wasp

Chrysis ignita, also known as the ruby-tailed wasp, is a species of cuckoo wasps. Cuckoo wasps are kleptoparasites– they lay their eggs in the nests of other wasp species and their young consume the eggs or larva of the host wasp for sustenance. These wasps have a number of adaptions which have evolved to equip them for their life cycle. Chrysis ignita parasitize mason bees in particular. Ruby-tailed wasps have metallic, armored bodies, and can roll up into balls to protect themselves from harm when infiltrating the nests of host bees and wasps. Unlike most other Hymenopterans, cuckoo wasps cannot sting. Chrysis ignita is found across the European continent.