What do i need to be aware of , when I gain size?

[CyberThread]

So I use to have a mount who was just a medium creature, and through various bonus, when I summon the creature, it is now huge.

What do i need to adjust for it, stats and abilities wise, because of the new size, compared to the medium creature?

[KillianHawkeye]

The most important thing is to know what its new space and reach are. Space for a Huge creature is a 15 foot square (3 x 3 on a grid). Reach is normally 15 feet for a "tall" creature or 10 feet for a "long" creature (most creatures usable as mounts), although exceptions certainly exist. The damage from its natural attacks also increases (there's a chart for that here. (http://www.d20srd.org/srd/improvingMonsters.htm#sizeIncreases) The method you used to achieve the size increase should tell you if the creature gets the normal modifiers to its ability scores and natural armor, or else give its own adjustments (more likely).

Additionally, be aware of your new size modifiers to attack rolls, AC, Hide, and grapple. Intimidate checks also carry a modifier based on the relative size of the intimidator and intimidatee, although you probably won't need to worry about that unless your mount is intelligent. You'll also have to recalculate carrying capacity.