Chekhov's Gun/Web Animation

"Eluamous: Why the hell did you make him do that? Schmoopy: Dude, I don't want to waste a perfectly good plot device we ended up spending, like, three episodes setting up just because we're not gonna end up using it!"
 * Unforgotten Realms subverts this by having Schmoopy cause his body to revert to wolf form... just because he might not get another chance.


 * A Mythology Gag referencing  is used at the beginning of the second season of Marvel Vs DC: Happy Hour. It becomes an essential plot point at the end of the season.


 * Mari-Kari subverts this with a scythe in the elementary school's groundskeeping shed, seen in the second episode. Despite the psychotic ghost slasher girl, it's never seen again.