Nuke Form

With a flash of nuclear fire, you suddenly transform into a radioactive monster, gaining the effects of a 7th-rank Elemental Form for 1 minute. You gain immunity to radiation in this form. Creatures struck by your tendril must attempt a Fortitude save against mild radiation sickness. This radiation uses the higher of your class DC or spell DC in place of the radiation's normal Fortitude DC, has an immediate onset, and the interval between each stage is 1 round (but it doesn't cause glitching).