Pretty much as the title says... where the fuck has it come from 
I rinsed the bath out with the shower as I usually do before I started running it so it deffinatley wasnt there. Has it actually come out of the tap?
Its about half a cm long, has a bit of a tail and two little ear prongs, very much alive and swimming. Sort of looks like a sea money but I dont think that's what it is.
I was quite looking forward to a bath, it's been a long day, but I wasnt keen on having company so I've had a shower instead.
tries to block out the thoughts of the little fuckers potentially coming out of the shower head