I registered and took a single class at a community college 4 years ago. Does anyone have a way of seeing it if I fail to record it on my list of classes taken?
Why risk it? If you get caught, you'll be in a ton of trouble. Do you want the possibility of being caught for such a stupid thing looming over your head for the rest of your career?
Did you fail the class or something? If it's a C or higher and your GPA is fine, it won't matter a single bit. If you're caught failing to record it, you could go through 4 years of med school plus residency just to have your degree taken away, etc.
They will know. There's a thing called National Student Clearinghouse that AMCAS is partnered with, and they have record of all the institutions where you took college-level courses.
Submit the transcript from that school and list the course or your application will be delayed.