Firebug was a game changer in frontend development, suddenly everything made sense and things got a lot more simple. Before firebug in the IE6 days, there was

Firebug was a game changer in frontend development, suddenly everything made sense and things got a lot more simple. Before firebug in the IE6 days, there was a script that you could inject into your page which created a draggable floating window in the document with a basic console and maybe some DOM view. I can't remember the name.