Cthulhu bathos

Recently someone was speaking to me about the pox-awful Underworld films, which involve a centuries-long war between vampires and 'lycans', which seems to be their made-up word for werewolves.

I'd never heard the word 'lycan' before, and was thus initially under the impression that the vampires were fighting lichens. Having since seen the last half-hour of one of the films, I can confidently state that this would have made for far better cinema.

The idea is even more appealing if the fungal symbiote of the evil lichen army comes from Yuggoth. It would of course be paired with killer algae.

On the one hand I can see how lichen could be a good natural enemy for vampires. It's pretty much immune to all their scary powers, when you think about it. But, on the other hand, why should it care -- what's in it for the lichen?