This is a poem I remember from an old nursery rhyme book: Solomon Grundy, Born on a Monday, Christened on Tuesday, Married on Wednesday, Took ill on Thursday, Grew worse on Friday, Died on Saturday, Buried on Sunday. That was the end of Solomon Grundy. from wikipedia: Originally, Salmagundi was type of salad with eggs and anchovies. Somehow salmgundi was corrupted into Solomon Grundy. Then the rhyme developed. Then the comics got hold of it and turned Solomon Grundy into some sort of monster zombie thing, called Solomon Grundy because he was born on a Monday. Solomon Grundy is also a band, of course.

The comic book character Solomon Grundy has been around since the Golden Age (he debuted in 1944), and was originally a foe of the Justice Society of America, and specifically the Alan Scott Green Lantern. This is significant because according to current continuity, Alan Scott was the protector of Gotham City before Batman came along. In the days of the oooold west, there was this old man named Cyrus Gold who was a miser, merchant, and a generally unpleasant person. Crooks robbed him, killed him, and dumped his body in Slaughter Swamp, just outside of Gotham City. Over the next fifty years, the muck and slime of the swamp bonded with the corpse and reanimated it. The plant-zombie hybrid then wandered into a hobo camp, where he claimed he could remember nothing except being born on a Monday. One of the hobos mentioned the poem, so the botanical zombie took on the name Solomon Grundy for itself. Here's the reason Grundy was an Alan Scott villain: being a plant-zombie, Grundy's body was largely composed of a nigh-indestructible wood-like substance, and Scott's ring was ineffective against--wood! Solomon Grundy was pretty much unkillable, since he was already dead. He had superhuman strength and stamina, and could absorb the kinetic energy of attacks and use it to boost his own strength--this is why he could get his butt kicked by Batman but still prove a match for Superman, since the harder you hit him, the stronger he gets. He had one other weird ability. His body could be destroyed with enough massive force, but whenever that happened, he would reform after a time back in Slaughter Swamp--sometimes with a different personality! Over the years Grundy has been a mindless brute, a gentle childlike creature, a gold-craving thug easily manipulated by other villains, and a few times, he's even been a cunning, malevolent schemer! That's the thing--when you destroy Grundy, you know he'll be back, but you can never be sure what kind of Grundy you'll be getting. Grundy, being unkillable and unaging, has been quite the recurring villain over the years, having been a member of lots of villainous teams and fighting lots of different heroes. In the pages of Swamp Thing, it was hinted that Grundy might have been an earlier attempt by mystical forces to create an earth elemental (like Swamp Thing was revealed to be), that simply didn't take. When Harvey Dent first became Two-Face, he ran into Solomon Grundy in Gotham's sewers, and the two struck up a truly bizarre friendship. And that is the end of (all I know about) Solomon Grundy.

The origin of the poem is linked to the origin of the salad/appetizer/spread. Yes, Solomon (Salman/Salamon/Solomond-a/et al) Gundy (Grundy/Gundie/et al) originally referred to a spicy seafood dish which may be a salad, an appetizer or a spread. Probably other parts of a meal with the same basic composition. This basic composition is smoked or pickled fish (often a smoked fish that is then pickled, usually herring), sometimes fish eggs, sometimes other meats, onions and/or such families (shallots escallions,et al) peppers, sometimes vegetables (tomatoes, lettuce, cabbage, et al), sometimes fruits and/or sugar, sometimes eggs and sometimes other herbs & spices (mustard, mayonnaise molasses, et al). Well how is it made, every recipe seem to differ on this. Thus was born the nursery rhyme. It was a mnemonic to remember how to prep the dish. How good a mnemonic is disputable because as time went by, the poem was divorced from the preparation process and I am still searching for the proper correlation. Some suggestions are that the poem starts with the fresh fish and the smoking/salting/pickling process to the actual prep of the dish while others suggest it starts with the smoked/salted fish and proceeds from there to the pickling and then the final dish. Still others suggest it starts from the already fully pickled fish and proceeds from there. One interpretation: Born on Monday -> fillet, salt and dry (smoke) the fish. First process. Christened on Tuesday -> prepare the pickling. (minced onions et al in salt, vinegar & pepper. Second process. Married on a Wednesday -> Add the pickling to the fish. Start of third process. Took ill on Thursday -> add other herbs and spices. Continue third process. Worse on Friday -> Add fruits and vegetables. Continue third process. Died on Saturday -> Allow time to Marinade for flavors to blend. End third process. Buried on a Sunday -> Serve, optionally with some garnish on top --fish eggs, fruit, croutons, et al-- (or on top of toast, crackers et al). ...And that is the end of Solomon Gundy! The first and second processes are independent of the third. That is to say, You could have prepared your pickling last week, smoke your herring this week and do the rest next week. Other interpretations of the mnemonic are just as likely so do not take this as factual. It is only theoretical and no more validated than the other interpretations.

I don't have an answer....but I am giving you as many points as I can for your question as it evoked so many really interesting responses, didn't it? Thoroughly enjoyed reading them...and, yes, I remember the nursery rhyme and haven't heard it for decades!!