Can any spell hurt it?

[SpiderBrigade]

Hehehe
Right now we know it is a Half-Dragon Spellwarped Pseudonatural Monster of Legend Tarrasque with extra HD.

The thing that's bugging me right now is the spell resistance 385. Tarrasque has SR 32, and 48 HD. Pseudonatural template adds SR of HDx2, max 25. Monster of Legend can give SR 10+1/2 HD. Finally Spellwarped gives SR 11+HD. At base HD, assuming these all stack, which they do not, it has SR of only 150. To get the full 385, you'd have to add 157 HD. If you don't break the rules by allowing stacking, it'd have to have...let's see...374 HD, or almost 8 times as many as the original Tarrasque.

Now, according to the rules for monster advancement, this beast should be CR 80 if you cheat and let the Spell Resistance stack, or a whopping CR 137 if you don't.

This is why it would help to see the full stats, because as it is, it looks like the only way you can get the listed abilities at the given CR is by bending/breaking the monster rules.

Edit: I suppose it's possible for the beast to have taken the Improved Spell Resistance feat multiple times. That could drop it down to 196 extra HD, or CR 94.