"Heralded."

So, I was thinking of a few different times Galactus picked a familiar face to serve as his herald, at least temporarily. First up, oddly enough, was Dazzler, around issues #10-#11, where she gets drafted by Big G to get his rebellious current herald Terrax out of a black hole and back to work. Why he picked her, I'm not sure, I haven't read those. I did read What If? #33 though, which spun off of that one: there Dazzler keeps the job so long, by the time she's able to return home, earth's a lifeless husk. Which doesn't narrow it down, but moving on.

Much, much later: Mark Waid and Mike Wieringo's last storyline on Fantastic Four was "Rising Storm," which I have in trade but not next to me, so going off memory: some aliens try to kill the Invisible Woman before Galactus gets her, since part of her powers was making invisible objects visible, which could show Galactus the aliens' hidden world. I think some powers are swapped, and Johnny ends up with Sue's powers and the herald spot. And Galactus gets turned back into the mortal Galen for a bit there...again, going off memory, but ooh, Quasar guest-stars! Reed calls him in, saying he can count it towards his back rent--which is intended as a callback to his series, when under his civilian identity Quasar had an office at Four Freedoms Plaza, but I have to call shenanigans on that. A straight arrow like Quasar wouldn't leave owing any money!

Another issue I don't think I picked up until much, much later: ROM #26: Galactus shows up to eat Galador, Rom's homeworld, and while the Spaceknights fight Terrax, Rom offers to trade his measly planet for a whole smorgasbord, namely the Dire Wraiths Dark Nebula. Which seems like a dick move, even if you've been at war with them for ever; but I think the Dark Nebula is so anti-life Galactus doesn't even want to eat it, and he gets back at Rom by moving his planet somewhere else. (He'd find it again eventually.)