In-N-Out Burger's signature Animal sauce is a cult classic, shrouded in secrecy. Fans swear by its unique flavor profile, adding a tangy, creamy, and slightly sweet element to their burgers and fries.

Stocking up on unused condiment packets is something all fast food lovers have done at some point, whether they're leftover from the time you ordered In-N ... it out. A change in the sauce's ...