Passed on by several people on Facebook, this Speed Bump cartoon, by Dale Coverly, of 3/25/09:
A cute portmanteau, of Pandora’s Box and inbox. And a comment on computer malware.
Turns out that there’s a compendium of cartoons about inboxes, with twelve items:
Rhymes With Orange 7/3/12, Candorville 5/9/12, Bizarro 2/18/12, Mother Goose and Grimm 11/2/10, Speed Bump 3/25/09, Arctic Circle 1/12/09, That’s Life 9/24/08, Mother Goose and Grimm 2/26/04, Speed Bump 10/1/03, Mother Goose and Grimm 8/8/03, Speed Bump 6/5/03, Speed Bump 5/23/03
The site samples only certain cartoons; you’ll notice that Dilbert is conspicuously missing from the list.