Is "he came up on some fungal cream" the same as "he found some fungal cream"?

Upon is one word and has a different meaning to up on. But to answer your question, yes upon is correct.

It should be “I just came upon some fungal cream”. It does mean he found some fungal cream, yes. But “came upon” it, normally means you weren’t really looking for it and just happened to notice it. Which if you’re combing through trash doesn’t entirely make sense. Perhaps he was coming through trash looking specifically for something else but found some useful fungal cream by accident?

To "come up on (something)" means to physically approach it. "We are coming up on Chicago" for example, in a car ride. Not to be confused with "something has come up," meaning an unexpected event that will impact plans. When pawing through trash, I would use "I came upon some fungal cream." "Upon" is its own preposition that is not necessarily "up"+"on."

[Yes](https://dictionary.cambridge.org/dictionary/english/come-upon)

“Came upon” and “happened upon” read similarly to me: this would imply that he wasn’t particularly looking for [whatever he found]. Without additional context, simply stating “he found” doesn’t indicate whether or not he was actively looking for the thing that he found.

Come across would be much more widely used in the U.K. than Come upon. But also, the context would be more common in past tense, like “have you ever come across this before” as in, have you seen it before. Probably more because there is less opportunity to use in the context of randomly finding something in the moment you weren’t looking for but is noteworthy.

This is a different usage than what you're talking about, but a "come-up" is or was apparently regional slang for a bargain, as mentioned in Macklemore's song Thrift Shop.

Yes but it sounds funny because the phrase, “he came upon…” is usually whimsical and seen in fantasy writing or children’s books. It’s like discovering something new and wonderful! Even surprising. So when i read “he came upon some fungal cream…” i laughed. Maybe he came upon a fungal monster but cream? 🤣 It’s more for an epic tale and finding a treasure or monster. I’d hear it in lord of the rings, Harry Potter or a fairy tale, not just very day speech. So i found your sentence very humorous.

"came upon some fungal cream" sounds like he was out strolling through a field or down a forest trail and just found it laying there.

I am so sorry. It is "anti fungal cream". I am anal.

To come up on just kinda means to move toward. To come upon means to find something, generally without looking for it in the first place. For me I would pronounce them with slightly different syllabic stress. “UP on” vs. “upOn”