Shibugaki

Shibugaki is the schoolyard bully, usually tormenting smaller kids or Tamao. When he first met Astro, he dismissed him as "a stupid pile of micro-chips" and refused to associate with him.

As time went on, Kenichi convinced Shibugaki to accept Astro and let him join their gang. Shibugaki is also afraid of ghosts

(Source: Absolute Anime)