what's the golden hammer for?

[save Palestine]

or golden paint roller or whatever that is
when you pick it up it appears at the top right just below your level

and how do i use it?

[Shirojacky]

If you have a Collab that can be upgraded into a Super Collab (by fusing it with the correct item, which needs to be maxed), you get the Hammer at lvl 50 or if you have several Collabs in your weapon bar. There are 4 Collabs that can be upgraded this way, and you need the Hammer to do it - once per run.

[SpectreChazer]

you can combine collab weapons with some related items. Like fire breath and gorilla hand.

[Juno Brier]

Once you get the golden hammer, look for a golden anvil.

In addition to the above, while there's 2 ways to get the golden hammer, you can only get 1 per run, thus only 1 super collab per run.

Each one is absurdly strong though.

[save Palestine]

ohhhh naruhodo, thanks everyone

[Carlton BEaEnkEs, no E]

I didn't know this either, thanks for the explanation to everyone who explained

[Harpy Hugger]

GOLDLEIOOOONNN HAAAAAMMMEERRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR