It Chapter 1 & 2: Every Monster Explained & Ranked
15. The Chinese Buffet
When the Loser's Club come back together at the beginning of the second movie, they meet at a Chinese restaurant for a meal and some pretty heavy drinking. That's where Mike reveals why he called them back to Derry and it's obviously also where they find out that Stanley "couldn't cut it" and killed himself rather than return.
After that fact is teased by the fortune cookies in a tense scene, everything gets pretty nightmarish as some of the other cookies begin to hatch into hellish monstrosities, including strange winged monsters, a crawling eyeball and bug-like entities. It's all very ghoulish and it's then crowned by the restaurant's giant fishtanks filling up with decomposing but animate (and creepily singing) children's heads.
And this is basically just the appetiser.