goal for the week: unrealistic
It appears there is a vampire moth (Calyptra thalictri) now, It was discovered by Vladimir Kononenko in 1999 in Siberia. Previously they they were thought to only feed on fruit but, it seems the males will also go for the blood of mammals. They have a hollow two chambered proboscis that they rock back and forth to pierce skin. Then the blood pressure pushes barbs out of their proboscis making them difficult to detach. They are also known to drink the tears of large animals such as elk. Vampire moths are thought to be completely harmless to humans as they are not known to carry any diseases and they take an extremely long time to pierce skin so would likely be brushed away anyway. The current theory for why the behavior developed is to provide a nutritional boost to the young that feed on mostly sodium poor meadow-rue leaves.