It could be a story or a movie straight out of the Hammer House of Horror series of films. You go down into the Underground in London to catch a Tube train and unbeknown to you, you have been chosen as its next victim, then be prepared to have this creature drink your blood. This is not any common creature but is unique to the Tube network, although there are now reports that it has taken up home in other Tube networks in other countries.
It lives permanently in the Underground system. It cannot live outside because it has become intolerant to the cold of the surface world. But it doesn’t care because it has all it needs down in the depths. It feeds on blood and it doesn’t care whether t comes from rats or other vermin. And when it gets a chance it will happily drink the blood of the human passengers.

Yes, I think this has all the makings of a good horror story, except that it is all true. There is such a creature and it wants your blood. So, what is it? Perhaps you might have already guessed, as the picture suggests, that it may be a mosquito of some sort. And you’d be correct, except that this is a new species that only exists in underground systems.
It has a bite which is painful and it is constantly after as much blood as it can take. And it is doing very well in its underground environment. It is estimated that it is breeding at such a rate that the numbers are increasing exponentially. So, how has this creature evolved? It appears to have evolved from a surface mosquito of the type culex pipiens which lives above ground. The change over time has become complete that biologists have said that it can no longer breed with its surface cousins.
The official name of this Tube-loving mosquito is culex pipiens molestus. It is a pretty apt name and for anyone not versed in Latin, molestus means troublesome pest. This seems to be most appropriate. So, I hope you enjoy your next journey on the London Tube!