That is the scariest thing I've seen since the movie "Aliens" LOL!

I didn't even know cosmos HAD tubers. But from looking I think you're right on circling the yellow parts as what would produce upward growth.
My guess on the purple circled roots are a younger set of roots.
My guess on the red circled part is an older root.
And the green circled clump: my guess would be the original little clump that has gone on to reproduce the red and purple circled parts.

Lots of good looking white roots in there too, so they must be healthy. I would guess you could separate this mass into at least 3 plants, but like I said, don't know anything about cosmos tubers.

Can you inquire at the bulbs forum here?

It's a perennial cosmos and closely related to dahlias. It's known as the "Chocolate Cosmos" because of it's chocolate fragrance. It grows very similar to dahlias, same bloom period and dormant period, both grown from tubers, etc. Thanks for the suggestion, if no luck here I'll try the bulbs forum.

Funny- I didn't know my Chocolate Cosmos had tubers until I dug them up & threw them out one year because I didn't know what they were- some form of weird weed, thought I! Needless to say when my beautiful chocolate cosmos didn't appear in the summer I figured it out & had to replace them because I LOVE the smell of them- good enough to eat--- now if only dahlias smelled like that I'd be in heaven with the thousands of them we have around here!

I'm definitely looking forward to that chocolate fragrance. I hope they live up to their name. Don't dahlias have "some" fragrance? I have lots of seeds for different kinds of dwarf dahlias and I could've sworn it says they fragrant. Is it very light?