a willy
The willies is when you get so nervous you feel like your brain is about to explode. It’s not because something scary is happening right now, but because it might happen soon. It’s like when your mom is watching you play video games and you know she’s about to walk in.
I got the willies when I saw my mom standing in the doorway.
The willies hit me when I forgot my homework.
The willies came over me when I saw the teacher walk in.