WMG / Super Mario World (1991)

King Koopa was Killed Off for Real.

Adding to the example from the cartoon above, Mario and Luigi in "A Little Learning" rig the lava pipe to have it flow into Koopa's bedroom. The episode itself ends Koopa screaming on his bed with the lava building up around him. The next episode, "Mama Luigi", happened to be the Super Mario World series finale and the last animated episode of the Mario Bros. franchise to date. Koopa was referred to by Luigi and only appeared at the end of his flashback, adding to the suspicion that the Mario Bros. carried out the dirty deed.

---