Crumble
From HGWiki
Caster Level: Druid 6
Innate Level: 6
School: Transmutation
Descriptor(s): Sonic
Component(s): Verbal, Somatic
Range: Medium (20 metres)
Save: Fortitude, negates
Spell Resistance: No/See below
Area of Effect/Target:
Duration: Instantaneous
Description: The target construct must make a Fortitude save or be destroyed. If the target saves, it receives CLd10 Sonic damage and its Fortitude save is lowered by 1 per 10 CL over 30.
Notes
This spell also works on petrified targets and certain specific creatures such as Narzugons (even though they are immune to petrification) however in this case you will need to beat their SR.