Costume of the Month for December 2000 is...
...Wrestler Spider-Man (From Ultimate Spider-Man)!
He Appeared in: Ultimate Spider-Man #3
This is from an alternate reality and all he did in this costume was beat Crusher Hogan twice and make $500. I decided to use this because my low expectations for Ultimate Spider-Man were disproved. Here is the normal realities equivilent:
November's Costume of the Month