Cat with Black Bump on Gum

I'll be taking Wally to the vet this week, but just wondered if anyone had this issue before and could give me advice - so as to test the vet and so I don't panic.
Wally is a white Maine Coon with all pink gums. I noticed a black spot on his gum the other day. It's a bump, not just smooth like a discoloration or mole-type issue.
I realize it could just be an abcess of some sort, but googling of course led to "mouth cancer" and freaked me out a bit.
It doesn't seem to bother him at all - eating drinking playing fine, not messing with it at all. They eat Instinct from Nature's Variety.

Any help would be appreciated.

Don't google!!
It can freak you out so much, that it is really not worth it!
Is the bump on the bottom, or top gums? Is it by any chance where the fangs touch the opposite gum?
Bugsy has bigger fangs, and because of that he has 2 bumps on the bottom gum, where the fangs touch it - it is a darker bump too, and it is normal...

might be the start of a rodent ulcer. I have had a couple of cats develop them. Just a possibility They are pretty easy to clear up with medication, but I believe they can reoccur.

Most of my cats have black spots on their gums, but when they start to swell, it tells me that they either have rodent ulcer, gum disease, or an injury (insect bite, bit themselves, tooth annoyance). If its swollen, you need your vet to look at it.