Ichneumon wasp,
Ophion obscuratus

I found this male in the house last night and brought him back outside. It's a nocturnal parasitic wasp species. Females look for caterpillars and inject one egg per host. The caterpillars remain alive until the wasp larva reaches its final instar. The adults feed mainly on plant sap and nectar and continue enjoying their lives. This species is one of the few that fly around even in winter. It's distribution area includes the entire Palearctic and Indomalaya.

Some representatives of the ichneumon wasps (not this one) carry a special virus in their genome and use it to produce virions, which after injection influence the host's behavior, metabolism and immune system.