His original Japanese voice kicks all sorts of ass as well.
Meta Knight goes up against the Puki flower, and it over powers him, then Kirby goes Needle on it, and cuts off most of it's heads, and pins it down. The day is saved and they all leave... until the remaining head gets back up and tries to eat them. Meta Knight tosses his torch at the plant and lets it burn to death.
In both parts of "Scare Tactics", Kirby managing to scare both King Dedede and Escargoon twice. The first time, he's wearing a jack-o-lantern and terrifies both of them. Then, during the second part, he's dressed up in a ghost sheet with flashlights. Both times he really sells the creepiness with his laughing. What's really epic though is that for the second scare, Kirby came up with it all by himself!
Sword and Blade's fight with Sirica in episode 60 "Crusade for the Blade". They may often be reduced to Cannon Fodder due to the Worf Effect, but the pair made a good showing against the formidable young lady.
Kirby defeating the Big Bad Nightmare in the finale, of course.