I'm Tin. I live in Croatia but i speak English. I have a Steam account. I'm the leader of SCRT (Sven Co-op rebel team).
It's not an Easter Egg actually. It's a trigger, it probably triggers some event.
triggers are invisible though. This is probably a test or something.
I thnik this is the trigger when the houndeye spawns in that big box.
You are not logged in, your comment will be anonymous unless you join the community today (totally free - or sign in with your social account on the right) which we encourage all contributors to do.
2000 characters limit; HTML formatting and smileys are not supported - text only
I found this easter egg in Half-Life: Source. When i went in there, i got teleported back to the sewer.