Crush the Chex cereal into fine crumbs in a ziploc bag or a food processor.

Mix the crushed Chex cereal, peanut butter, powdered sugar, and vanilla extract in a large bowl until well combined.

Chill the mixture in the fridge for about 30 minutes to firm up.

Scoop the chilled mixture into balls, about 1½ tablespoons in size, and roll them in your hands to smooth them out.

Melt the chocolate in a double boiler or in the microwave in 30-second increments, stirring in between, until fully melted.

Dip each puppy chow truffle into the melted chocolate, making sure to fully submerge it, and place them on a parchment-lined sheet pan to harden.

Wait for the chocolate to fully cool and harden, then roll each truffle in powdered sugar to coat.

Store the puppy chow truffles in an airtight container in the refrigerator for up to 5 days.