I finally found the video that Pierce The Veil makes fun of Fall Out Boy in!!!! So there was minor conflict between the two after Fall Out Boy released a cover of Beat It after Pierce The Veil did.

"Pierce the Veil had a minor feud with emo band Fall Out Boy. Fall Out Boy recorded a cover of Michael Jackson's "Beat It" prompting Pierce the Veil to point out that they'd recorded their own cover only months before - the implication being that Fall Out Boy had copied them. Not long after, Pierce the Veil released a video on their youtube channel that parodied Fall Out Boy in a series of tongue-in-cheek skits.

The Fall Out Boy feud prompted some media outlets to point out the similarities between the bands' song-titling styles (both commonly use long, descriptive names). Vic Fuentes responded by saying that Fall Out Boy was usually trying to be clever or funny, whereas his titles were more serious and often taken from his own poetry."

Gee whiz, thanks Songfacts.com!!!!!!!

So anyway, in the beginning, it's Fall Out Boy (someone mentions Pete xD) watching TV and seeing Pierce The Veil. Then, at the end, they mention they'll copy their idea.

^^If it didn't show up before