Claud Pincer, known as Hasami Chiyokichi (狭見 千代吉 Hasami Chiyokichi) in the original Japanese version, is a boy who frequents at the Big Wave store in Echo Ridge.
He has no backstory in the game; he simply wished to test his own power against Geo/Mega Man, though Omega-Xis deduced that since FM-ians are drawn to a human's loneliness, Claud met Cancer because he apparently had no friends, which Claud verified. While Cancer does not have evil intentions like many of his FM brethren, he and his human partner are boastful and pride themselves highly on their skills in battle (Omega-Xis even guesses that this personality is why he doesn't have any friends).
In the anime, he is a cocky and determined third grade student who was saddened by his lack of friends, resulting in his encounter with Cancer (who accidentally merged with Claud when he was trying to merge with the security guard throwing Claud out of Sonia Strumm's concert). He is a die-hard fan of Sonia's, and is targeted by Cancer after failing to get into one of her concerts without a ticket. Unlike other EM Wave Humans, Cancer Bubble retained Claud's voice and personality, and the transformation is rarely complete (thus, Cancer Bubble is often still wearing Claud's clothes or hat). His seiyū is Wasabi Mizuta and his English voice actor is Brianne Siddall.
Claud Pincer is the 3rd Grader who happens to appear in Big Wave after Cygnus Wing's scenario. Now that he can fuse with Cancer who also shows up, he wanted to have a battle at the wave road in AMAKEN foyer.
In MegaMan Star Force 2, he shows up again in Big Wave. After Yeti Blizzard's scenario, he wanted to have a battle in the wave road at Grizzly Peak Slopes. He has very little link power, only 30. He's obsessed with defeating MegaMan.
In the anime version, Claud Pincer was trying to sneak inside Sonia Sky's concert without a ticket but he got kicked out by the security guard. Before the security guard puts him down, Cancer fuses with him by accident. As Cancer Bubble, he couldn't get inside the concert again so he causes trouble with bubbles. MegaMan arrives and tries to stop him and uses Tidal Wave. MegaMan, having been hitted lost his ticket and Cancer Bubble found it. He became so happy that MegaMan lost track of him. Unfortunately, the security guard thought Cancer Bubble's face was a mask and ordered him to take it off. He used the bubble trick on him and causes another havoc at the concert. Sonia saw the attack so she Wave-Changed into Lyra Note and confronted him. Her stage was damaged and she was almost defeated. She tricks him by singing with him so that he is caught off-guard for a moment. After Claud's "favorite part" of the song Lyra Note hits Cancer with a shock note. Cancer is defeated and Claud Pincer was freed. He finally gets the chance to hear Sonia Sky sing.
In the Tribe version, he celebrates with Sonia Sky and the other people at the end.