Iowa Code § 421.8: Penalty for defective return under certain circumstances.

If a person files a purported return of tax which does not contain information on which the substantial correctness of the self-assessment may be judged or which contains information that on its face indicates that the self-assessment is substantially incorrect and the conduct previously referred to in this section is due to a position which is frivolous or a desire which appears on the purported return to delay or impede the administration of the tax laws of this state, then the person shall pay a penalty of five hundred dollars. This penalty shall be in addition to any other penalty provided by law.