1. Place 2 packages of cream cheese, taco-flavored cheese, and margarine in a mixing bowl. Let stand at room temperature for 30 minutes. Add milk to the cheese mixture in the mixing bowl. Beat with an electric mixer on medium speed until combined, stopping the mixer occasionally to scrape the bowl with a rubber spatula. Cover bowl and chill 4 to 24 hours.
2. Form into a head shape and place on a serving plate. In a bowl, stir together the remaining cream cheese until smooth. Spread head with softened cream cheese. Press in tortilla chips for ears. Using wood picks, attach a pickled whole pepper for nose, pimiento-stuffed olives for eyes, and pepper-stuffed olives for toes. Cut zigzag peppers for eyebrows. Use shredded beets for hair and press in carrot sticks for teeth. Serve with assorted crackers. Makes 20 servings.