Grease a large tube or bundt cake pan with 2 teaspoons of the oil, and set aside.
In a large bowl, mix the popped corn with the M & M candies and the peanuts.
In a small saucepan, melt the butter, remaining 1/4 cup of oil, and marshmallows over medium-low heat, stirring occasionally. When melted, pour over the popcorn mixture, and stir to combine. Pour into the prepared cake pan, pressing down to fit. Cover with aluminum foil to keep moist and let rest until firm, 3 to 4 hours.
To serve, invert the cake pan onto a large cake plate or platter. Shake gently to release. Serve at room temperature.