Mr. Crocker used this suit in order to find invisible Timmy or a fairy using the suit's heat-seeking fairy goggles. He managed to find invisible Timmy while he was invisible, meaning that the invention actually works.
It is a metal suit which covers nearly all of Crocker's body. Over Crocker's eyes are green-tinted retractable "heat-seeking fairy goggles", which he used to find Timmy while he was wished invisible.
After Timmy Turner wished himself invisible to avoid a beating by Francis on the last day of school, he started causing mischief throughout the school while invisible, drawing the attention of Mr. Crocker, who jumped to the immediate (and correct) conclusion that Timmy had wished himself invisible using his fairies. Crocker had this suit stored in a crate inside the janitor's closet, which he put on and immediately set out after Timmy. He ran into Principal Waxelplax, who told him to stop frightening everyone at the school. Crocker ignored her and nearly caught invisible Timmy, but he escaped into the auditorium to collect his attendance award while Crocker was left behind the kitchen after being covered by flour.
His suit now colored white from flour, Crocker appeared in the auditorium to further harass Timmy in front of the entire school, but was beaten up by Wanda, who turned from an animal bat to a baseball bat and smacked Crocker around until Timmy was given enough time to wish himself back to normal. Crocker grabbed the now-visible Timmy and showed him to the school, but he was too late and nobody believed his accusations as usual. Principal Waxelplax caught up to Crocker, and when she saw his suit covered in white she assumed he was the one causing the mischief earlier in the school. Crocker is then taken away by security who beats him up as punishment.