Rerere no Ojisan, a neighborhood street-sweeper, is recognized for his unique verbal quirk of exclaiming “Re re re?” instead of the standard expression of confusion. Originally nicknamed “The ‘Are You Going Out?’ Oji-san” for habitually inquiring about passersby’s destinations, his name later solidified around his signature phrase. He sports a bald head, elongated ears, a mustache drawn as horizontal lines, three prominent teeth (two upper, one lower), and a yukata paired with geta sandals, his broom perpetually in hand. While his yukata appears yellow in most *Tensai Bakabon* adaptations, it shifts to deep green in the 1988 *Osomatsu-kun* series.

A widower with 25 children—five sets of quintuplets—his chaotic parenting years demanded constant sweeping to manage their mess, a practice he retained even after they grew independent. Flashbacks portray him younger, clad in a yellow business suit with black hair, starkly contrasting his elderly visage. His twin brother, Yoyoyo, shares his likeness but bears facial contours resembling the katakana “yo,” occasionally causing mistaken identity.

Though typically laid-back and committed to cleanliness, he adopts a stern tone when confronting littering or interruptions to his work. His calm disposition often gives way to bafflement amid the surrounding absurdity, punctuated by his confused catchphrase. Narratively, he serves as an observer, questioning characters’ actions or reacting to their antics with bewilderment.

His design, influenced by Shigeru Sugiura’s artistry, transitioned from vague early sketches to a finalized appearance. A visually akin minor character in a *Tensai Bakabon* spin-off episode playfully hints at a possible in-universe link.