When I first got into makeup, I saw several youtube gurus using a product called eye primer. It was so foreign to me. I've never seen my mom use it so really, it felt unreal to me.
And so I continued observing gurus here and there and they all say the same thing. That primer helps eyeshadow adhere better and keeps it from creasing. After a while, I bought my first primer, also from ELF, but in a stick/cream form. After getting sick of that, I tried this other primer in this doe foot applicator packaging.