Can I put chocolate syrup into yellow cake mix to make it like swirl type cake?

Or will the chocolate syrup get burnt or something. should I wait till it's partially cooked and then add the chocolate or just not add it? I \want a yellow cake with chocolate marble swirl, please. Thank You.
Update: Do I swirl it in before I start to cook it(the cake mix and chocolate syrup)? thanks.
Update 2: So mix the syrup with the cake batter (one cup or whatever)together because the syrup weights too much and will sink to the bottom?

I've never use the inside of an oven before.
Update 3: Thanks, but I only have chocolate syrup for hot chocolate and ice cream.
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