After Jimmy started to lose his hair, the Collector sentenced him to imprisonment on a world with Prof. X, the Silver Surfer, and Moondragon.

I suspect Universo is behind this.

Alternate version: Jimmy is turned into a Brain-Globe of Rambat.

On second thought, make that a Brain-Dome of Rambat, just half a globe. Or half a brain.

The fact that Jimmy was never transformed to a brain in a globe suggests to me that there's at least another 150 issues worth of Superman's Pal, Jimmy Olsen to be written!

Especially the one where his transformation is a prank being pulled on him by the Legion of Super-Pets!

And then there's the one where Jimmy accidentally gives Darkseid the Anti-Life equation, only it turns out to be Johnny Quick's super-speed equation, with hilarious results!

Or the one where the Superman Revenge Squad mistake a Brain Globe Olsen as an ally and end up performing a series of good deeds, though Jimmy has to keep coming up with reasons why they are secretly evil ones!

And then there's the story where all of these transformations and serums leave Jimmy bankrupt, so he is confined to a world where each of his guises has enough change for one phone call.

Yep, you guessed it: "The World of Dimed Olsens."

Traveling through time, he hit an anomaly which split him into five different copies of himself, was captured by Evillo and held for ransom on Tartarus in "The World of Damned Olsens".