Boo-chan, alternatively called Bo-chan or Botaro Ikawa, attends Futaba Kindergarten as Shin-chan's five-year-old classmate in the Sunflower Group. His slow, expressionless demeanor contrasts with notable intelligence and interests in artistic or mature subjects. He passionately collects uniquely shaped rocks and investigates urban legends, mysterious phenomena, and UFOs, claiming knowledge of Japanese locations for rare stones.

He speaks deliberately yet surprises peers with insightful comments. A constant trail of mucus from his nose serves as a distinctive trait, occasionally manipulated for tricks. During group role-plays like house games, he consistently chooses animal roles, especially dogs or cats. After kindergarten, he regularly observes craftsmanship at a local Kasukabe tatami-making store.

His mother appeared once in the original manga, while his father remains undepicted. As a dedicated Kasukabe Defense Organization member alongside Shin-chan and friends, he shares strong bonds with Shin-chan, Masao, Kazama, and Nene. He shows particular understanding of Shin-chan's unconventional behavior, often joining his imaginative games, and Masao finds him comforting during emotional moments.

In "Densetsu o Yobu Odore! Amigo!", Boo-chan proves pivotal when samba-dancing doppelgängers terrorize Kasukabe. He first alerts the group to urban legends about clone replacements after visiting a new mall. His rumor expertise helps them notice disturbing adult behavioral shifts, including teachers'. During the group's escape with Shin-chan's family and agent Jackie, Boo-chan leverages local terrain knowledge to advise a rugged mountain route against clones. With Nene and Masao, he evades capture by clone mothers, regrouping at a park before being taken to the antagonist's base. There, he witnesses konjac-based clone mass production.

A future depiction in "Super-Dimension! The Storm Called My Bride" shows adult Boo-chan in his mid-twenties as a roboticist and inventor.