1a. Is it Arion ater? Y -> Arion ater
1b. Not so -> It is a different slug
Although to be fair mating Leopard slugs on my back garden shed was one of the more spectacular wildlife sights I've ever seen in the flesh.
Now I've started looking at slugs a bit more I find I'm growing quite fond of them though. Been browsing the excellent FSC guide and familiarising myself with what's about, what's likely to be in my locale and what sticks out like a sore thumb as ID features. This both draws ridicule from my more sensible wife (for what amounts to browsing animal/plant/fungus catalogues) and prepares me for decisions to be made in the field. On this occasion a pale pinkish slug with some dark pigmentation and a very pale breathing pore meant it was a new slug for me and one which had a chance of being identifiable
My other half would still not be over the moon if she knew I was looking at live molluscs in the house, although there's every chance she knows and is turning a blind eye, bless her cotton socks.