Electrocute - Surprisingly, Your E will count towards the Proc, It is extremely good (Even Manco1 is using it, For those who don't know He is a Grandmaster Teemo Jungle Player)

Cheap Shot - Your shrooms will proc this, Giving them some extra damage

Eyeball Collection - Just for the extra oomph

Ultimate Hunter - Don't have to focus on CDR items for your R, Is pretty nice and in big battles you would easily snag kills via Poison to get the stacks required

Triumph - Occasionally will save you in a pinch if you get a kill

Coup De Grace - DOT begins to do more dmg as it goes, Also useful for anyone running away and steps on a shroom when they are low

Chilling - My personal preference so enemy champions cannot get away, and also allows for allies to close in easier

Challenging - Bit better for extra burn

This is a decision on play style

Flash - You are still an immobile Champion, So flash would be the preferred secondary spell

For Jungle you want to start off with Q, To avoid any unnecessary dmg from Jungle camps.

Your W is used mainly to move from camp to camp and avoid being caught out early. No need to stream points into it unless you want a better speed boost early.

You would max E to allow for quicker clear, AOE camps becomes easier with this.

You would put points into R ASAP, Longer throw ranges = More strategic shroom placements

Hunters Machete and Refillable

Guinsoo's Rageblade - Gives some AD/AP and AS, Helps to stack your E
Berzerker's Greaves - To further increase Your AS
Nashor's Tooth - AP/AS, Helps to make AAs hit like a truck with decent burn from the AP
Bloodrazor - for the AS, Helps clear somewhat
Liandry's Torment - Stacked with Quinsoo's it allows for extra burn, Increasing DOT for E and R

I usually get Quinsoo's built before anything, Zerkers into Nashors tooth (For extra AP/AS)

It may seem weird, But Deaths Dance actually can allow you to Solo baron and occasionally go toe to toe with anyone who decides to run face first into you.

I occasionally grab Runaans instead for the wave clear, Seeing as you can easily stay within a Bush/Jungle and shroom it up, It allows for you to split push even better

You could also through in any other AP or AD item you prefer

Any highly mobile burst Assassin Champion can easily deal with you, High CC Champs are your bane.

Melee based Assassins have a harder time, Such as Ekko or Akali. Akali Especially because you can still get a basic idea of where she is in her shroud via DOT

Always keep on eye for Pinkwards and if the enemy team get sweepers (Try to space shrooms so they wont all get shown if a sweeper is used)

More front line champs, Allowing for you to sit back and gun anyone down if need be.

Heavy CC champs work well aswell, Allowing for you to stack up your DOT easier.

This is my preferred pathing, Hopefully it helps

You Generally won't gank unless the enemy team is pushed very far up, Rush for 6 and place shrooms to serve as a defense for your team against Ganks

You generally want to keep smite for AOE camps if possible

1. Red Buff - Helps to keep you healthy when clearing aswell as extra DOT

2. Blue buff - Mana Regen and CDR

3. Scuttle (Optional) - Scuttle for an easy kill

4. Gromp - The first 5 hits will hit through your blind for some reason, Gromp has a weird buff that allows for that

5. Murk Wolves - Q the Larger one then AA the smaller ones 3 to 6 times then focus the larger one again

6. Raptors - Try to kite to the best of your abilities, DO NOT FOCUS THE LARGE RAPTOR, The smaller ones will do more dmg. I generally Blind the Large Raptor then kite around hitting the smaller ones

7. Krugs - Blind Ancient Krug and focus the medium one, Kite it around, Try to keep a smite charge for this

Inferal - Your best friend, Extra dmg is always a plus

Mountain - Helps if you need to split push

Cloud - Helps with not getting caught

Ocean - Passive healing, Good for your laners