This mod reskins the chainsaw to give it a Dorothy theme. I would have loved to make it look like Dorothy's chainsaw, but that is far beyond my ability, I'm afraid. Instead, I went with a chaotic, splatter look because I think it fits her personality. The color scheme is taken directly from her sprite.
(Speaking of which, you should check out stellaglowstuff.tumblr.com if you're interested in the game's sprites, music, backgrounds, etc.)
It also replaces the sound files for the startup and attack sounds; unfortunately, because it uses scripting, it doesn't work on official servers. I tried it without scripting, but replacing the chainsaw_high_speed_lp file also causes issues due to the differing loop points.
One thing to note is that when cutting something (zombies, boxes, walls...), the chainsaw sound effect changes pitch to reflect the cycle speed slowing down (or whatever the technical term for it is). Because 2 of the 3 possible loops have a voice line in them, they will also change to a lower pitch if they play while attacking something solid. While I think this is creepy and therefore worth keeping, you may disagree. If so, just contact me and I'll upload a version without the mentioned loops.