To be fair, it happens every week with comics. The reason it “always seems to” happen more often with hot books is because some people will get re-orders in super quick on those buying as many copies as they can to flip or sell at a mark up, and eat up the available copies as the distributors, well before anyone has had a chance to report or look at the state of their shipments.
Seeing as how she (?) is mostly like lightning, I’m going to say cover A is 1st cover too!
The last page does show a lightning creature (she) identifying as the Mjolnir (the God of Hammers ?), but the cover shows - a blast of lightning from the God of Hammers NOT the God herself. Maybe the inevitable second print of #20 will have the last page as the cover. Then, #21 will have the full appearance in the book but not on the cover.
Then it will be,
First cameo - Thor 20 (reg.),
First cover appearance - Thor 20 second print
First full - Thor 21 (reg.)
Thor 20 though could be a cameo and a full first, unless the lightning figure has more detail in 21.
I am still trying to find a copy of both. Will try my luck tomorrow at the LCS …
Yeah, I’m doing away with these stupid silly terms that people like to twist and work the way they feel to justify if they’re selling the book or not, etc… From now on, it’s just first appearance, second appearance, first cover appearance… and so on… they’re all appearances.
Also I think cameo as a term used on a “new” character that no one even knows about is silly considering the actual definition of “cameo”, which is normally a “well known character” that makes an appearance outside their normal title or show, etc. Like say Superman makes a brief appearance in a Batman title on the last page that no one was expecting to show up, that’s a cameo appearance according to definition.
Calling it like it is:
Hulk 181…2nd appearance, 1st Cover.