Glow in the dark mushrooms

So I was reading this thread:

http://www.gardenerscorner.co.uk/forum/threads/some-new-guys-to-add-to-my-collection.101097/

And the glow in the dark mushrooms caught my eye.

Seems there are a few places online that sell cultures.
Is this genuine?
Do they really do this?
Or is it some sort of scam?

 

I grew some a couple of years back, I was bought a kit as a get well present when I broke my ankle. The spawn was placed in a jar containing sterile wood chips. The mycelium grew quite rapidly and in s completely dark room gave off the slightest pale green glow ( also called fox fire - Google it!). The mushrooms are said to glow brighter but I never managed to get any.