A rather odd one from rakugaki-biyori's "bump on the head" Pixiv Fanbox series. This happens, then both Reimus decide the other is some kind of evil mimic (the rebus thought balloon to convey this is Reimu standing with her shadow behind her developing an evil grin) and a danmaku battle ensues. Unfortunately someone engrossed in a book gets caught in the crossfire: Sendai Hakurei no Miko, the fanon/MUGEN character that's Reimu's immediate or distant predecessor. A large cartoony bump growing on her head, the shrine maiden from a more violent era cracks her knuckles (impressive trick without hands) and puts both Reimus in their place. With matching bumps and brooms they clean up the mess as the elder shrine maiden goes back to her reading.