I think it's more interesting when we don't know

Im gonna imagine its a big fluffy panda then..... With a knife.. And s chainsaw...

Nah, it's gotta be the Kool Aid man.

Does the monster eventually break through the door? Or does it wait for you to get into the vent no matter what?

You drown before it gets the chance to break the door.

Could even have just been the door buckling under the pressure of water.

I Think it's either a Prisoner Juggernaut, or the Bogeyman since he's very important to the story and tryig to get to Murphy.

I think it's a Juggernaut, and always assumed it was. I mean...if it were the Bogeyman, he could easily just break down the door with his giant weapon...

I don't know what it is, but man that part scared the living shit out
of me for some reason. It felt like a nightmare, you know the dream where you're being chased, for me that is what it felt like.


I think it should remain mysterious, because the fact that we don't really know what it is, is what is so frightening about it.

But I do have a theory, it might be

^

Did this part remind anybody else of the Pinky introduction in DOOM 3?

Didn't get that far in Doom 3. I wasn't a big fan of that game.

I am pretty positive it is a juggernaut. Perhaps it's something else, and the game does a decent job at leaving this scene ambiguous, but logically it is a juggernaut because Murphy fights one a few minutes prior to this sequence and they are the strongest of the prison enemies.

...I could have sworn it was

If I had to guess what monster it was, I'm pretty sure I'd choose the juggernaut just because of the nature of the dent-making and the flexibility, mobility of the thing when it goes to first person. Anyway, I honestly believe it's similar to SH2's prison cell monster, or SH3's red light, in that you don't really know what it is, but it surely freaks the hell outta you.

It's probably a Juggernaut, but I like to believe it is a unique enemy (similar to the Blood Sucker from SH1, or the sewer monster from SH3) that is supposed to remain a mystery.

i suppose it would be juggernaut since he plays a great role in this game.

Most likely a juggernaut, not sure if it would fit in that tight space though.. But a minion wouldn't be able to break that door down.