Pop the popcorn according to the package directions. Transfer to a large bowl along with the pretzels.
Melt the butter, marshmallows, and salt in a medium saucepan over medium-low heat, stirring, until smooth, 5 to 7 minutes.
Fold into the popcorn and pretzels until combined. Let cook slightly, 2 to 3 minutes. Fold in the chocolate-covered peanuts. Using your hands, form the mixture into 16 mounds (about ¾ cup each).