Google is testing displaying and popping up the auto-suggestions auto complete search terms in the search bar when you scroll back up towards the top of the search results.

Here is a GIF of it in action captured from Valentin Pletzer who posted a video of it on YouTube and Twitter:

Here is the longer video of it in action:

I am not sure I like this feature, it can be a bit in the way and not the best user experience. But hey, Google is always testing.

Brodie Clark also spotted this:

Forum discussion at Twitter.