This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Return of the Living Dead
Tar Man. Oh dear God, Tar Man. The other zombies are no slouch in the nightmare fuel department either, especially the zombie in the mausoleum in II, and all of the zombies released from the Trioxin canisters in III.
The idea that, no matter how much damage you inflict or what you do, the zombies will never die. Headshot? Nothing. Dismemberment? Just more pieces to come after you. Nuclear strike? Good job, now you've spread the infection even more. Extinction just seems inevitable.
Actually, electrocution and burning kills them. You just shouldn't do the last one because that just turns the virus airborne as well.
Only if the smoke comes out a tall chimney and mixes with rain clouds. The soldiers in the second film burned the "surviving" zombies with flamethrowers, and there was no mention of further spread.