is ghosting a job bad

So i’ve been applying to a lot of jobs and i finally got an offer from one place. (retail btw not like a salary based job) Ive been signing things like for background check and got my schedule. i start in a few days but i recently just heard back from a different retail job that im really interested in. I got called to come in for a second interview and im not sure what to do if it works out and i get a job. i dont want two jobs and im most likely to go with this one. would it be bad if i ghost the job i got an offer from??