Quit job without resigning?

Legal...sure.. However, ghosting a job can follow you...

Ok. Do not put down Walmart as a reference. You will have to say you were unemployed during that time and hope no one from Walmart happens to come in when you are interviewing.

Its legal, if you ever need them for a reference you're kinda screwed and they may screw you over a bit on the last paycheck (though I'm sure you'll get it eventually). There is no law that you have to give notice to quit a job.

Good for you?

It's not good for your future jobs. If any future employer contacts Walmart and finds out you are a ghost and a flake, you are not getting the job that you might actually want, later on.

They can sack you on the spot without notice for the simple reason that they don't want you tomorrow.
For the same reason you can walk without giving any notice.
It doesn't look good on a resume though.

There is a warrant out for your arrest.

Why did you quit?

If you walk out, not having worked a formal notice, the company can LEGALLY keep ALL the money you have earnt since the last pay day as compensation for leaving them short staffed.