Overview
This answers what happened to the cat what barney had nightmares about.
What exactly happened to the cat?
The ”CAT” was mentioned by Barney in the opening section of ”Red Letter Day” In kleiner’s Lab.
Before I say why I need to say a few things so you can understand what I’m saying. In Kleiner’s Lab there’s a mini teleporter what you can teleport small props in. If you put yourself on top of it the machine explodes and you get the achievement ”What Cat?” anyways let’s say the reason.
In Half Life 2’s Beta in Kleiner’s Lab you can hear extended dialogue from Barney saying that cat went ”Inside Out”
If you listened to what I said about the achievement you can understand what happened. The teleporter worked but it worked the wrong way. The cat turned inside out and it got mangled.
The Voice Line
Yes it says right side out to make it look like a cat. Because it was inside out until he un inside outed it
[link]The Mangled Cat Model Image (Found in the game files and is a mixture of a human and a cat to make it mangled??)