I don't know what it could be. Sounds like the fuel pump kept turning on and off, too. Has happened on and off for the past 2 weeks. Battery looks a little wet on top. Car is completely stock save for the muffler. Happens a few seconds after the car turns on. Torque shows voltage flipping out.

VIDEO: https://youtu.be/ymFkVH1vDXc

 

It has some symptoms of canbus communication issue, do you currently have any OBD plug in?
Also when all dash light is on and everything is acting wired you may want to start off cleanning your battery terminal/post and chasis ground, it is extremely rare tha all these things fail at the same time.

 

Correct, I have an OBD adapter. I unplug it when I turn the car off. I just checked my battery terminals and cables, and my negative cable appears corroded.

 

Unplug the OBD adapter and clean the battery for any corrosion (baking soda is your friend wrt to battery acid) on the battery and chasis ground to see if anything has changed.

 

I replaced both battery terminals and cleaned my battery posts, as well as dabbing on some dielectric grease. I did the 20-brake stomp to reset nvram plus the whole battery reset procedure. The problem seems to be fixed, but the idling did act up for a tiny bit on the first startup. Idle is fine now and the car is working as normal. For now...