Homebrew Monster (3.5) PEACH

[Surgo]

Tiny creatures with more than 6 hit dice are problematic. They don't do much damage

I'd call spellcasting as an 18th level sorcerer pretty good "damage".

Giving a creature at that level a CR greater than its hit dice is extremely problematic due to a number of spells. Actually, the CR of this is problematic period because it's the ultimate glass jaw, and glass jaws don't make much sense CR-wise. If an 18th-level character breathes on it too hard it will die. You should figure out if that's desirable or not.

In addition, what's up with the huge numbers? DR 30/- is something of a 3.0ism, but it doesn't hurt to have it I guess. With SR 35, though, you might as well just say "immune to spells from anyone who didn't cheese their caster level". Is that what you want?