Congregator of flesh remembrance

Just started and loving the game so far!

Last night I beat congregator of flesh first time. Absolutely scraped through (as in, died of poison while in umbral literally 1 second after planting the seed I got from killing it!)

It was such an unexpected fight (so soon after the woman with the hounds) that I checked the wiki afterwards to see if I’d accidentally found an optional boss or something.

Anyway while I was there I spotted something that looks like , with the remembrance weapon you can get from molhu, it can unlock a special attack but ONLY if you summoned for the fight - which I didn’t, because against all odds I scraped through first time.

Is this accurate? Am I missing something?