Brandon's Dusclops

Brandon's Dusclops is Brandon's most powerful non legendary Pokemon

Biography
Dusclops first appeared in Gathering the Gang of Four, where it faced off against Ash's Charizard. After a fierce battle, Dusclops managed to defeat Charizard due to its high defensive power and immunity to Charizard's most powerful move, Seismic Toss.

In Pace - The Final Frontier, Dusclops provided a considerable challenge for Ash's Bulbasaur, despite having been worn out from battling Charizard. In the end however, Bulbasaur managed to knock out the Ghost type with a Solarbeam attack.

Trivia

 * Brandon's Dusclops is the only Pokemon that was not fully evolved to have defeated Charizard since it evolved from Charmeleon (any battles in which Charizard refused to battle don't count).