For years, movie makers and directors have been trying to get viewers to re-watch their movies. In addition to intriguing plots and a diverse set of lovable characters, directors and scriptwriters have been adding seemingly unnoticeable additions to their movies. Informally called “Easter Eggs,” these changes can be anything from the charm on a necklace to a character from a different movie making a quick appearance.

Of course, these additions are never crucial to the overall story line. Most viewers don’t even notice them. But for the people who do, they provide a small connection to other movies in that franchise. Disney and Marvel are two companies who seem to thrive on these little Easter Eggs.

Marvel’s Captain America: The Winter Soldier is filled with references to other Marvel superheroes and movies. When Nick Fury (Samuel L. Jackson) first reveals some new technology to Steve Rogers (Chris Evans), he indirectly mentions a scene from The Avengers, when Tony Stark (Robert Downy Jr.) finds himself trapped in a massive turbine. While anyone who has not seen The Avengers won’t understand that reference, it does not add anything to the plot, making it unnecessary to understand.

While most people may have noticed that one, a smaller, even harder to recognize symbol can be found on Natasha Romanoff’s necklace. While some may fail to notice the arrow charm hanging around her neck, others connect that to another hero’s weaponry. Hawkeye (Jeremy Renner) from The Avengers is almost always seen with a bow and arrow, leading some fans to believe this choice of jewelry was intentional.

Disney has also been fond of making connection to their other movies. While Rapunzel and Flynn Rider are usually confined to their own movie, Tangled, they make a quick appearance in Frozen during Elsa’s coronation. While they are only on screen for a couple seconds, many fans noticed the couple walking into the city just as Anna is leaving the castle. Just before this, during the song, “For The First Time In Forever,” one of Rapunzel’s paintings makes it into the castle’s gallery. Later on, when Anna visits the trading post, a miniature Mickey Mouse doll can be seen on one of the store’s lower shelves.

While these Easter Eggs do not really add too much to the overall plot, they give fans an excuse to go back and watch the movie again.