This is something I thought about, about Attack on Titan. ⚠️WARNING if you are planing on watching the anime/reading the manga, but haven’t started/finished yet, don’t read this, it will contain spoilers⚠️
In AOT, the titans eat humans. And to become a titan-shifter, you have to become a titan and then eat a titan-shifter. What if while being turned into an average titan, there’s this little part in their brain, that tells them to eat a titan-shifter so that they can have a human form again. But they just don’t know who’re titan-shifters and who aren’t, so they just eat humans in hopes of them being shifters.