My mom and I tried to recreate the picture of us at her PhD defense at my PhD defense

When you're a doctoral candidate, you need to publish original work and defend it in front of a panel of impartial PhD experts in your field. They grill you about whatever aspect of your research they'd like, and then they remove you from the room. While you're gone, they deliberate about how you did and make a decision about your defense. If they decide you were successful, they'll call you back in to the room and give you the good news. From then, you are called Dr. Tanuki86 (or whatever), and you are deemed an expert in this field. Your education is complete and you are considered post-doctural. Typically, you'll become a researcher or a professor at this point..

And if not, do they shove a pole up your ass and hoist you up the flagpole as a warning against other failures?

We don't talk about them

Wow that’s neat. Thank you for the info, @jasonmon