Don't forget the venerable <blink> tag and the obligatory "Under Construction" GIF.
https://i.imgur.com/7mr0vjQ.gif
in seventh grade we had a "web" class that, as an assignment, wanted us to find "pen pals" on the internet (lmao great idea), and to make a personal site about whatever. I made an Escape Velocity site. Lots of under construction gifs even when I submitted it.
Which ones were your favourites?
(perl's OK, CGI had a lot more server side injection risk from what I remember)
If the former, the injection vulnerability would be in the script talking to the server/database via CGI, rather than in CGI itself.
If the latter I don't remember any major unpatched vulnerabilities in CGI.pm, but it was epically inefficient.