You can punch Superman in the face all you want, and it won't get you anywhere. But smart villains know you can do much more damage if you skip his body entirely and punch his mind. For as much as Earth's yellow sun gives Superman, it can't protect his feelings--he has to do that all on his own. Spoilers follow for My Adventures with Superman Season 2, Episode 8.
"The Death of Clark Kent"
That's the conceit of this episode of Superman. Jimmy and Lois have finally met up with Kara, and it's time for them to have a sit-down and figure everything out. Meanwhile, Brainiac is making himself comfortable inside of Clark's head, trying to figure out what makes him tick.
The latter storyline is the meat of this episode. It's pretty reminiscent of one of the later episodes of Superman & Lois Season 1, when Tal-Rho strapped a similar device to his half-brother's head and took a tour through his mind, stepping through all of Clark's memories while Clark's mind tried valiantly to resist.
I don't mind that creators like to go back to this well when looking for a weakness to exploit with Superman. Kryptonite only gets you so far, and magic only works when you have an expanded DC Universe with characters like Black Adam, or are doing comedy with Mr. Mxyzptlk. Going into Superman's mind allows writers to skip right around all the punching and flying and focus on the way his mind works. Things are more complex there, especially with a Superman as young as this version is.

This is, of course, a great way to recap the show quickly, without spending a whole episode on it, and then to dig into why none of that actually matters in this moment, because the place where Superman is vulnerable is in his heart. Brainiac tries some hamfisted ideas, manipulating Superman's memories in hopes of turning him against Lois, only to finally realize that Lois took care of that for him just days earlier when she broke things off with Clark in a moment of fear.
Superman is a wildly, unimaginably powerful character in almost every incarnation. He's spun the Earth in reverse, restarted the sun, outrun The Flash, and more. Watching him punch stuff is fun, but we need to care enough about the man in the suit to enjoy the punching. If Brainiac couldn't stop Superman by getting into his mind, Superman would eventually just punch a hole through his ship. It wouldn't be terribly exciting.
What makes Superman interesting is remembering what makes him human. He doesn't see himself as a god hovering above earth, his sense of nobless oblige burdening him. He sees himself as a regular guy, raised by regular parents, with a special gift that gives him the privilege of protecting everyone on Earth. If he was that golden god, Brainiac's tactic wouldn't be terribly effective. We know that Superman would rather hug than punch in 100% of situations, though, so seeing him like this makes us worry.
Meanwhile, Lois, Jimmy, and Kara are all trying to put their differing versions of their relationships with Clark together to make them make sense. Jimmy has become a peacemaker (but not The Peacemaker) and steps easily into that role when Lois and Kara come to blows. When thinking about recent incarnations of Jimmy Olsen, this is one place where My Adventures excelled and where the Arrowverse struggled. Mehcad Brooks was a fine enough actor, but Supergirl never really made us believe that James was Superman's Best Pal. He was imagined first as a potential love interest for Kara, and his story with Superman was second to that. He was more believable as The Guardian than as Supes' personal photographer.

This version of Jimmy, though, we have no doubt. This dude adores Clark, and he adores Superman. He'll dump out his pockets to help him. He'll commit federal crimes and put himself at very real, personal risk to save him even though he's just a guy. He's also allowed to be a goofball, but the only person who's really made him look stupid so far is Lex Luthor.
This episode is a great display of what makes both Clark and Jimmy who they are and why that matters. I think Lois and Kara come out looking good, too, but this is a great reminder of what makes Clark Superman and why Jimmy really is his Best Pal.
