From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Chichi was first seen using the helmet's features by throwing it as boomerang blade when she decapitated a T-Rex who was chasing her, and disposed of its remains with its laser. Right after that, she used the laser to try to hit Yamucha because he had scared her, but she was knocked out by him instead. When she first went to the Kame House with Son Goku, she launched an attack against Muten Roshi with its blade to try to test him, but he comically failed, leaving the blade stuck in his head.
Chichi's Helmet is seen in any video game where she appeared as Kid Chichi. In Super Dragon Ball Z, the helmet, along with the rest of her childhood clothing, can be unlocked as an alternate costume for Adult Chichi.
Chichi's Helmet is one of the height treasures found in Stage 1 of Dragon Ball: Revenge of King Piccolo.