How ap rengar got fed

Just lost a game to a troll build, whats new?
Trying the things that they see on Youtube
But now it's fine looks like this game's going alright
Not a strange item in sight
Alright this is what I like
A simple ordinary 5v5
But somehow I feel something isn't right

Where the hell did all my HP go
It was there just a second ago
I thought his magic damage was too low
So i wanna know...

How'd AP Rengar get fed?
I try to farm and I'm dead
Walk out of base and I'm dead
So I wanna know...
How AP Rengar got fed!

He started with Doran's Shield against you
'till DFG my whole team had no clue
He's on the prowl and I know he's got me in sight
There's no way I can survive
Just look how fast I just died
Instantly deleted from the fight
Didn't even have a chance to kite

How is this even working? I don't know...
Is this guy really 17-0
With only one AP ratio
So i wanna know...

How'd AP Rengar get fed?
I try to farm and I'm dead
Walk out of base and I'm dead
How AP Rengar got fed

I think were fine, looks like we just won our first fight
It's only Rengar alive, he can't fight us 1v5
Group and push their towers we have time!
But somehow I feel something isn't right

Where the hell did all my team mates go
They were here just a second ago
But he let me go and now were bros
Tell me, why
Did he just kill me again