Viper’s Bugloss is unusual as it is the name for two entirely different things:
1 A common
European plant "Echium Vulgare" also known as Blueweed, which has rough, hairy leaves and the flowers start off pink but turn blue as they mature;
2 A
European moth "Hadena Irregularis" which flies from July to August, believed extinct in the UK due to loss of habitat;
So despite sounding a bit sinister, it’s just the name of
a couple of nature’s minor oddities.