This is a weird one, but Astepro nasal spray for allergies. The name brand is a little unpleasant to blast up my nose because of the smell/taste. But the off brand stuff is absolutely foul and bitter. I would get random whifs and drips of the nastiness in the back of my throat for an hour.
I think you missed the point here. This shooter had no opportunities prested to him. He wasn’t smart enough or connected enough to ever be comfortable, let alone actually do something noteworthy. Being on the news for a day or two is the only “fantasy” he could possibly achieve. It not about causing a sea-change, it’s just about getting noticed.
He wasn’t born a monster, but violence was the only obvious route to having any impact on his surroundings.
American society loves guns and hates helping poor people, this is what we get.