Teemo; A Small Decision-Making Change
I will try to make this brief, and nothing I am suggesting will change how Teemo is now, but adds a decision making mechanic to his Toxic Shot (E). One form will be the same as it is now, but you can turn it off for a different form (which is why nothing needs to be taken away elsewhere cause its a this or that mechanic)...
Basic Attack Range: 500 units (just stating what it is now)
Teemo's Blowgun (E): Static Cooldown: 2 seconds; [Toggle ability, renamed to better fit the idea] Toggle ON: Teemo's basic attacks deal 10/20/30/40/50(+30%AP) bonus magic damage on-hit plus apply a poison for 4 seconds dealing 6/12/18/24/30(+10%AP) magic damage per second.
Toggle OFF: Teemo's basic attacks gain 80/110/140/170/200 units bonus range to his basic attacks and deals 10% base attack damage as bonus physical damage on-hit, this bonus damage can critically strike.
10% base attack damage is because Teemo has low base AD because of Toxic Shot's bonus damage; so it actually is not increased damage it is just normalizing his damage with the other marksmen without changing his base stats. This is mostly only an AD Teemo thing and it doesn't hurt AP Teemo at all cause nothing is changed, and having a decision making effect will just feel better to play as since then Teemo can decide whether he wants to sacrifice his range for damage or sacrifice his damage for range; also the ranks are 580/610/640/670/700 units range for those that have trouble adding. I went with a change like this as since Teemo has a full out marksman play pattern and kit already (Move Quick helps him kit, he is full damage, and a ranged sustain damage dealer) might as well just have effects that play around that and he will be the objective and map control marksman with his shrooms and stealth passive.