It's always fun to go back over TV shows and movies that existed before the social media era, to discover how showrunners and filmmkakers hid (what we now call) Easter eggs and other pop-culture references in their work.
Here's a great example: a fan of the 2000s X-Men: Evolution animated series managed to spot a most unexpected Easter egg in the series: a moment that was animated in direct reference to the '90s teen drama / horror cult-classic, The Craft:
[GIF] Can anyone ID the pictures on the left? The Craft (1996) and X-Men: Evolution (2000)...? from r/Marvel
As you can see above, this moment of the X-Men girls walking down their school hallways is shot-for-shot taken from The Craft, which was first released in 1996. That movie saw four high school misfit girls who were into witchcraft unite to form their own coven, and rise to power the top clique of their school. Of course, their power begins to corrupt them almost immediately, leading to a violent rivalry between the most troubled girl in the group (Nancy), and the "good witch" (Sarah). The film was a who's who of '90s stars, with the principle four witches being played by Neve Campbell, Rachel True, Robin Tunney, and Fairuza Balk. Also starring in the movie were then fresh faces like Christine Taylor, Clueless star Breckin Meyer, and Scream's Skeet Ulrich.0comments
X-Men: Evolution was released at the time when the live-action film series was just making a splash in theaters. The series caught its fair share of criticism for the way it transformed the X-Men and their lore into a Young Adult reflection of itself, as well as drastic character changes like "Goth Rogue." However, for an entire generation of fans, Evolution was *the* definitive animated take on the X-Men, paving over the '90s iteration, X-Men: The Animated Series.
As stated, it used to be easier for animators and filmmakers to sneak these kinds of homages and Easter egg references into their works when there wasn't a culture of fans scrutinizing every detail of a show, and then sharing those details on social media. In this case, it was the "wisdom of the crowd" that helped these dots get connected, and fans like us (and hopefully you) are better for it.