Hi and this is my build for Rumble tested it a lot and would like to share it!

I know my runes may seem illogical to some players but just test them and you'll see they work. Having a little bit of everything isnt bad and the magic pen early game boosts ur damage a lot.

For the masteries i take 0/21/9 cause of the flat hp and increase in AP/AS. Also 4% reduced damage is good when you are in a tight situation.

I start with Dorans shield. After that its good to rush for Sunfire Aegis but if u cant handle well its preferable that you get Boots. After that its a straight Mejai's Soulstealer, Rylai's Crystal Scepter, Mercury's Treads, Will of the Ancients and finally Rabadon's Deathcap.

If there aren't too many disablers you can go with Sorcerer's Shoes.
If u like to use overheat late game its wise to swap the Will of the Ancients with Hextech Gunblade and get Lich Bane instead of Mejai's Soulstealer

For summoner spells i take Ignite and Ghost, some prefer Flash but i personally think that with Ghost and W skill u can chase down anyone who has flash.

im gonna start with the cons:

-Very risky build if not well farmed
-Has built in self silence which can screw u over anytime if ur not paying attention
-Doesnt work 3vs3
-U get focused a lot

Pros:

-Very hard to kill
-Good escape and chasing abilities
-Very high damage output both AP and AD
-Can slow massive groups of enemy heroes
-Very good pusher/harraser

well i hope i've helped please COmment and vote !!!