spoilers... obviously.

As we know, Vecna's clock chimes correspond with the amount of kills he needs. As said by hiddenremote.com, "The four chimes of the clock correspond to the need for four kills which will then open the four gates Vecna needs to sweep back into their dimension." (yes i did a little bit of article reading for this leave me alone i was checking my facts)

Vecna (or Max) was not killed in the finale, and of course, as anyone would be, he's angry. Really angry. We're only left to assume that he wants to get revenge. This is where the clock and its chimes come back into play.

If you listen to the chimes that play while the gate through Hawkins opens, something is different. (https://youtu.be/XJM6HOECIXs) The first set has 4 chimes. For some reason, the second has 5. If you aren't the smartest person on Earth, 4+5 = 9.

There are 9 people in the party.

Dustin, Lucas, Mike, Will, El, Steve, Robin, Nancy, and Jonathan.

Yes, Joyce, Hopper, and Erica, are important characters, but the 9 mentioned before have the most connection to Max. (This includes Murray and Argyle, too.)

I'm assuming that those 9 chimes are meant for the 9 main party members. Vecna's about to go ham on them 💪💪