Mr. Krabbs, collecting food supply for the patties at the Krusty Krab.
Even though the Krusty Krab is based on your typical burger-and-fries restaurant, there's not much to suggest that the patties they use are made of beef. They're underwater, and don't seem to have much contact with the surface world, given how much Sandy feels like an outsider. And given that the citizens are all quite small species (sponge, crab, fish, squirrel), beef patties might be too big for them, anyway. So what might they be using instead?
Why not egg yolks?
Egg yolks are actually full of nutrients for growing embryos, so they're probably a great meal. In fact, I think this might actually be why Boss Salmonids have golden eggs in the first place-they need all the energy in the field. Not to imply that the Salmonids are eating their young! (Although that isn't outside the realm of possibility in marine life) Inside the Golden Eggs is a fish skeleton, not an embyro-I think Golden Eggs are just Salmonids that didn't fully develop, so the yolk has gone unused. Likewise, this isn't to suggest that the Krusty Krab is a cannibal hangout. None of the residents look like Salmonids, and they're likely just eating the yolk. But customers might still raise some eyebrows at the origins of their food-so, naturally, Mr. Krabbs would want to keep his identity hidden.
I know crossover theories tend to have no canon basis, but we actually do know that some form of Spongebob exists in Splatoon's universe, because we had the Spongebob/Patrick Splatfest in Splatoon 1. Of course, if they're just TV characters, this theory is out the window. (There's also the question of the appearance of humans in some episodes of Spongebob, but Spongebob has been known to be full of canon errors....)
