I found a recipe for a Mexican condiment called Green Mayonnaise, it may be the mystery ingredient, I don't know. Here it is:

I cup mayonnaise
1/4 cup minced roasted Anaheim or New Mexico chile
3 garlic cloves, roasted and mashed
Fresh Mexican lime juice, to taste

Combine all ingredients and mix well. Refigerate for at least 1 hour.

I just posted a recipe, I am officially a boring house wife. Hope it helps.