<human>: Some background:  I've been working a retail job for the last two and a half months, and on Saturday put in my two weeks because I'm going to be moving to another city.  My boss had been expecting me to stay at the very least through the Christmas season, but an opportunity appeared suddenly, and I jumped on it.  When I came in today (payday), my boss handed me two paychecks and told me that I would not be needed for the full two weeks.  I asked whether she wanted me to work today, and she told me that I could leave if I had other things to do (she had already shaken my hand and wished me luck, and seemed very final about it, so I took it as a hint to leave.)  As I was leaving, I clocked out and told her to not worry about the fifteen minutes or so I had worked today, and she replied that it was fine and that she had paid me for a full day today.  So essentially she had handed me a second paycheck for a day of work that she had not insisted I do.

Here is my issue.  This is not a kind woman; she's honestly a snake, and I've seen her go out of her way to make life miserable for people who have inconvenienced her on a number of occasions.  I'm worried that she's going to somehow use the fact that I didn't work for this money to screw me over (accusing me of fraud or something, I don't even know).  I don't know whether I should just cash this check and not worry about it, or call her up and tell her that I'm not comfortable being paid for time I didn't work.  Any advice?  Could this come back to haunt me?

Condense the text into a few key points
<bot>: My snake of a boss paid me for a day I didn't fully work when I quit, now I'm worried she's gonna screw me over if I cash the paycheck.