Yes Gexman you are quite right on the Rylai's instead of the Frozen Mallet, I too think it is a better choice if you are going full AP. The other things I would like to say are the Boots of Swiftness and Madred's Bloodrazor are not for a AP build, it would be a better choice if you picked Sorcer's Shoes, Nashor Tooth, or a Malady because it would be a lot more effective in a AP build. Good job with the guide and other items though.

This is my first comment on mobafire, so feel free to correct me if i'm completely wrong here. That being said: If the purpose of this build is shrooms and darts, wouldn't rylai's be a better option for a 4th item? It's a little bit more pricey, however you still get the HP boost (a bit less) and a 80 AP instead of 20 AD boost. Yes the downfall is your auto-attacks wont have a chance of slow, but your blind has a 35% (might be wrong on that) chance of slowing and hes usually pretty good at escaping anyways. But this is just my opinion, you've obviously played this type of teemo quite a bit more than me, so i'm sure you have your reasons. I'm just curious as to why I guess. Otherwise i'm excited to start trying it out, I <3 shrooms.