In Pathfinder, most creatures take up no more than 30' square. However, this size doesn't really do justice to a number of larger creatures, should I want to model them. Being, frankly, exceedingly disappointed in the published quetzalcoatlus, I want to stat my own, but to do so I need to figure out how to deal with creatures significantly bigger than the baseline for 'Colossal'. Surely such a creature's controlled space should be much larger than 30'X30'!
Given that I'd like the creature to have a 60'X60' space for an aerial combat:
- what should its size modifier be for CMB/CMD stuff?
- what should its size modifier be for Stealth checks?
- what should its size modifier be to AC/attack?
- what should its size be for stuff like Wind Effects and Swallow Whole and Reduce/Enlarge Person?
- what should its reach with its bite attack be? It's got a disproportionately long neck, but also most of that space estimate has to do with wingspan.
Best Answer
30x30 is not the limit for a colossal creature's space, its the standard. From there it only goes up.
If you look at the kaiju, you will see that colossal creatures are not limited to 30x30 space (only one of them is actually 30x30). There is even a kaiju that takes a 80x80 space.
The design of colossal creatures is so that if you need any larger stats, these basic rules for sizes (AC penalty, CMB bonuses, str/dex penalties, etc) are no longer a significant aspect of the creature, and instead, you should look up for (or design) abilities that reflect the creature's size. For instance, all kaiju have 40+ strength, so the size bonus on their CMB is minor compared to their overwhelming strength.
With that said, do not bother to adjust the size modifiers of colossal creatures, simply increase the stats and grant the creature abilities based on their enormous size.