Largest monster you can think of.

[Starwind]

What is the largest monster you can think of?
Not including creatures (or deities) that can resize themself to anything they wish or living planes like Neth.

I think from the Epic Level Handbook the Xixecal is pretty damn friggin big. It has White Dragons circling around it's shoulders.

I'm actually looking for something gigantic to throw my party up against since they are getting way too cocky (and overpowered).

 

[der_kluge]

A Titanic Titan with a permanent Enlarge?

Titanic being a template from MM II.

The book of Templates has an "Apocolyptic" template, though I'm not sure if it increases the size or not. I think it does. Of course, the CR also ends up being 50+ for such creatures, so that's probably not for you.

 

[Azure Trance]

My first thought was a turtle that holds the earth on its back.

Pffft, I know, why bother fighting that.

 

[Starwind]

Well basically I was just wondering what the biggest (naturally-sized) monster was people could think of.

The part about putting it up against my PCs is just an afterthought, and I wouldnt necessarily have something that they could beat, just something to kill a couple of them and make the rest soil their armor in fright.

 

[Krishnath]

Try a Great Wyrm of any dragon type you choose, and then advance it to, oh, 100 HD or some such, it's guaranteed colossal+ (check your copy of the ELH or Draconomicon™ for the details of advanced dragons).

 

[BOZ]

Jormangundr, the Midgard Serpent?

 

[Shade]

Zaratan and Soarwhale from Arms and Equipment Guide.

Devastation vermin from ELH.

The recently converted H'Calos on the Creature Catalog.

And of course, the ever-popular tarrasque.

 

[Starwind]

Zaratan and Soarwhale from Arms and Equipment Guide.

Devastation vermin from ELH.

The recently converted H'Calos on the Creature Catalog.

And of course, the ever-popular tarrasque.

The Tarrasque is a tiny girly monster!

 

[Shade]

The Tarrasque is a tiny girly monster!

Your party must be cocky!

Try a corrupted zaratan (using the corrupted creature template from the BOVD). That's an island-sized turtle that deals 19 points of vile damage with every hit!

 

[Starwind]

That was just a joke, actually, my friends previous campaign he ran with some other guys killed the Tarrasque in How the Mighty Are Fallen so I'm taking that as canon for my campaign (ie; it already happened).

Edit: What book is the Zaratan in? I remember seeing it but I don't want to crawl through all my material.

Double Edit: Haha, I didn't realize you already said what book he was in.