A cameo is a small but special appearance or role by a well-known person, often in a movie or TV show, where they play themselves or a fictional character for a brief moment. Full definition
This is the cover shot of a very small cameo in a recent feature. (screenanarchy.com)
The reasonable man is one such objective standard, often used to determine tort cases and even occasionally making cameo appearances in contract law. (duhaime.org)
Make sure you stay until after the credits for a bonus scene that includes a very special cameo from the first movie. (fatmovieguy.com)