Does anyone know where the script reference ... payload.gosidekick.net ... comes from?

Question

I have an ASP.NET MVC 4 project that I am working on and I noticed that I have a script failure. I looked into it and discovered an unexpected script tag in my code, requesting a file from ... payload.gosidekick.net ... I do not know what this is or where i comes from. I have a number of plugins in the page so I thought maybe one of them was injecting this reference. I commented out ALL my script files and this tag continues to get included!

I cannot seem to find where or how it's getting injected and cannot tell from googling around whether it's harmful or not.

Has anyone had the same experience? If so, were you able to figure out how to get rid of it?

Thanks, G

P.S. Interestingly enough this is not in the VIEW SOURCE, I only notice it in Chrome when the site executes which means that it must be getting injected at runtime (?)

UPDATED This is the link that is being injected

<script type="text/javascript" src="http://payload.gosidekick.net/delivery/ds_SHPRTY49D12X.js"></script>

Answer 1

Reposting comment as answer:

If it only happens in Chrome, it's probably coming from a Chrome extension. Does disabling any extensions you have installed fix it?

Update: I did some digging and found what I think is a copy of the source code. Based on that, it looks like the script placed/replaced ads on websites at random. I also found this G+ post talking about it so looks like it was quite a bad extension.