Anon is suffering from the intense heat as he's walking down a road on top of an embankment when a Marisa-Reimu couple demand sweets as toll. He tells them if they're collecting toll, they should be in the center of the road instead of on the white lines, and puts the Marisa there. The hot asphalt scorches her feet, and paralyzes her.
Reimu goes over to save Marisa by rolling, but Anon takes Marisa's hat as a way to shelter himself from the sun. He finds it rather smelly due to river water, and Reimu starts attacking Marisa for having no hat, thinking Anon is her mate. After she kills Marisa, Anon decides he rather not wear that hat, and puts it back on Marisa's corpse.
Another Reimu shows up, and calls out the rest of the clan when she spots Marisa's dead body. They immediately accuse her, and Anon confirms it. Reimu runs away by rolling down the embankment, and the rest of the yukkuris follow except for a Patchouli. Anon warns her that the drying river is going to be dangerous soon, but she thinks they'll be fine.
He then grabs her hat and puts it on, finding it better than Marisa's, and puts her on the asphalt. Patchouli, unable to take the heat, throws up paste and dies. Anon then continues on, thinking he'll get some orange juice as the siren that marks the dam opening sounds behind him.
FunkSoulBrother said: I think everythin Anon did here was quite deliberate. What makes you think he's oblivious?
There were a series of anko stories featuring an anon that seems to be unaware of the detrimental effect that his actions are to yukkuri. Even his earnest attempts leave the yukkuri in a worse situation than before he arrived. Not exactly ayazou levels of incompetence, but the anons were in fact hypercompetent--in fact, they were too good whatever they do wrapped right back to torment yukkuri. Example: post #27369