This is right after GLaDOS reactivates, all the panels in Test Chamber 19 are 'waking up' and kinda twitching and spinning a little. You'd have to see it in motion but it's very creepy looking.. like tentacles coming down to grab you.
Currently Running Portal 2 at:
1600X1200 resolution vsync turned on.
8X anisotropic filtering
graphic settings, High & Very High.