Hi

I was wondering what colors you would think could make this green?

https://www.google.com/search?q=mike+from+monsters+inc&tbm=isch&tbo=u&source=univ&sa=X&ei=Dky6Ua7gHIfsqAGquoCoDA&ved=0CCwQsAQ&biw=1600&bih=775#facrc=_&imgrc=YfuTvv2_y3XFjM%3A%3BOo9bAzywYR49IM%3Bhttp%253A%252F%252Fimages2.fanpop.com%252Fimages%252Fphotos%252F4200000%252FMIKE-monsters-inc-4207219-1024-768.jpg%3Bhttp%253A%252F%252Fwww.fanpop.com%252Fclubs%252Fmonsters-inc%252Fimages%252F4207219%252Ftitle%252Fmike-wallpaper%3B1024%3B768

Ok I'm not professional but to me he look's like he is almost lime green. Just a little darker. Why don't you use Americolor electric green to start. Then if you need to darken it. I would use a little leaf green. Good Luck!

As a color specialist, I agree with punkin90. Leaf Green or Forest Green will help darken the color. If the electric green looks too 'raw' you can tame it by adding a touch of it's compliment. The compliment of green is red, and since this shade of green has a lot of yellow in it, you could also add a touch of purple. 

Try the slightest amount of red to start and add a touch more if necessary. The purple will help if the green starts looking too warm, or orangey. HTH