Make Sure He's Dead

A doctor gets a phone call from his best friend, and the frantic voice at the other end says "God, oh God, my wife's dead! I shot her! What do I do!?" The doc tells his friend to calm down. "OK, now the first thing is, you have to check to make sure that she's really dead." He hears silence at the other end, then a single gunshot. "OK, that did it. What next?"

—Old joke

When a character subverts No One Could Survive That by making sure the dead person stays dead. Can be done with bullets (sometimes lots of bullets or special types), fire, explosives, molecular disintegration, or a wooden stake, depending on what's available. Probably the most effective way of dealing with a Zombie Apocalypse, assuming you can disable the victim in the first place and that you can find the body afterwards.

One of many calling cards for the Dangerously Genre Savvy. Related to There Is No Kill Like Overkill and Rasputinian Death (if it's only the subsequent attempts that work). Failure to do this causes a response similar to Why Don't You Just Shoot Him? (in this case, Why Don't You Just Shoot Him Again?). See also: Double Tap

As a Death Trope, Spoilers ahead may be unmarked. Beware.

Examples of Make Sure He's Dead include:

Anime and Manga

Part 3 of JoJo's Bizarre Adventure has the Big Bad decide to make sure that The Hero is dead. Taking it one step further, he decides to do it not by going over to the body (and thus giving our hero a chance to attack him, which is indeed his plan) but instead by beheading him from a distance with a stop sign.
Sometimes, this backfires badly. In Rurouni Kenshin, Big Bad Makoto Shishio originally worked as a 'manslayer' during the rebellion, but for for some reason, his employers decided to get rid of him. They knew just how tough he was, and sent a small army after him, including firearms. And when he finally went down - after killing more than half of his assailants - they decided to make REALLY sure he was dead... they poured oil over him and set him on fire, essentially cremating him on the spot... but of course, it wasn't enough, and Shishio SOMEHOW still survived, albeit with third-degree burns covering his entire body, and thus turns into the 'Bandaged up like a mummy' baddie we know.
Though it is not shown the Blonde in Gunjo is implied to have done this.
When Naruto attacked Kakuzu with an attack that quite literally tore him apart at the cellular level, Kakashi moved in afterward to ensure he was dead. Which was needed, because Kakuzu actually was still alive.
The bad guys in Ninja Scroll blow up nearly an entire river trying to kill the protagonists. They're pretty sure they probably killed the heroes, but the leader of the evil ninjas says "it's better to err on the side of caution" and the comb the river for bodies.

Comic Books

In the first issue of the comic book miniseries Black Orchid, this is done to the title character using fire, as a followup to lampshading Why Don't You Just Shoot Him? and shooting her. This is on the second page.
In one of Toyfare's "Big Shots" strips, an assassin justifies cutting a mark's head off to his partner as making absolutely sure the job is done. He then chalks his shooting of the body multiple times after decapitating it up to spite.

Film

Scream, where the Final Girl Sydney, cold as ice, puts a bullet right between the eyes of the killer when he wakes up. "Not in my movie."
Rule #2 of surviving in Zombieland: Double Tap.
In Jeepers Creepers, when Trish and Darry are confronted on the highway Trish runs The Creeper over. When Dary asks is Trish thinks she's really dead, Trish shows her Dangerously Genre Savvy nature and proceeds to run him over not twice but five times. Unfortunately, it got better.
In Sin City, after Hartigan's bullet causes the assassin chasing them -Roark Junior- to crash, he tells Nancy to pull over so he can go back and confirm the kill. Unfortunately, while they're looking for him, Junior manages to sneak past them and stow away in their car.
In The Godfather, Sonny is killed by a small squad of mafia hitmen. One of these hitmen showers his corpse with bullets, spraying his body from top to bottom to make sure he died, then kicks him in the head.
In the movie adaptation of BloodRayne, the protagonists decapitate fallen vampires to make sure they're really dead.

Literature

One of the students in Battle Royale took advantage of being issued a bulletproof vest and getting a motorcycle helmet to trick opponents by pretending to have been shot and then taking them when their guard was down. Unfortunately, this trick failed when Kazuo Kiriyama made sure to put a bullet in his brain to be certain.
In Mage: The Ascension novel "The Road To Hell", the Technocracy soldiers sent after Seventeen are ordered to make sure he's dead. He's not, but with all the magi-tech modifications they did to Seventeen he probably could have survived a few dozen rounds to the brain anyway.
This trope is invoked retroactively to make Hogfather antagonist Teatime's introduction even more creepy and badass.

Teatime: I checked his breathing with a mirror, just like you said.
Lord Downey: Yes, I understand his head was several feet from his body at that point.

The World War Two novels by Sven Hassel frequently mention that veterans never pass an enemy corpse without putting a bullet through it.
Subverted in the Knight and Rogue Series. After Michael is tossed of a cliff the mooks are ordered to go down and make that he didn't break his fall with anything on the way down. Not wanting to treck down a cliff and back up again, they pretend to go down and return saying he died.

Live-Action TV

Stargate SG-1: After taking down the genetically-altered Monster of the Week, Vala dumps another clip into it "just to be sure."
Stargate Atlantis: Subverted in "The Defiant One" when Sheppard seems to kill a Wraith, then puts a few more rounds into him for good measure, only for the Wraith to get back on his feet and start shooting back.
Jack's Advice to Kim in the second season of 24

Jack: Is he dead?
Kim: I think so
Jack: Shoot him again.

The comedy show Whose Line is it Anyway? says this: "He tried to murder me. When you kill someone by chopping off their head, wrapping the body in a carpet and lighting it on fire, you better make sure they're dead."

Tabletop Games

In the crime noir RPG Dog Town, player criminals are urged to put three bullets, called "to-be-sures," into the heads of those they kill.

Video Games

Either bleed people out (ground headshot) in MAG or risk an enemy medic getting them back up again.
At the end of Mass Effect, Shepard orders this on Saren after the latter either falls in battle with your squad or commits suicide. Subverted when Sovereign reanimates Saren's corpse as a husk, even after one of your party members plugs him in the head one more time.
- In the multiplayer of Mass Effect 3, the enemies get in on the action. Losing all your health only knocks you down, where you can be revived by an ally or by using medi-gel before bleeding out. However, any nearby first-tier enemies (Cerberus Troopers, Geth Troopers, and Cannibals), if left alone, will execute downed players, killing them off for the rest of the wave.
This is generally a good idea in Dead Space.
After the player defeats Jack Lupino in Max Payne, the next storyboard sequence begins with Max putting another half-dozen rounds into Lupino's body. Whether it's an example of this trope (and a sensible precaution given that Lupino was high on something best described as "PCP meets LSD") or Max simply getting a bit carried away is left slightly unclear.

When Lupino finally went down, I wanted to make real sure he'd stay that way. V was a bad monster, turned them into freaking zombie demons from outer space.

In EP6 of Umineko no Naku Koro ni, Erika, unable to invoke detective's authority to determine that the "corpses" she investigated were dead or alive, decided to guarantee their death in a different way: by beheading them.

Web Original

Evil Overlord List Rule 13:

All slain enemies will be cremated, or at least have several rounds of ammunition emptied into them, not left for dead at the bottom of the cliff. The announcement of their deaths, as well as any accompanying celebration, will be deferred until after the aforementioned disposal.

From the "The List of Character Survival Techniques v1.5":

31. Confirm your kills
In gun games, ammo is rarely so scarce that you can't spare two bullets to splatter a body's head. If ammo is scarce, refer to fantasy rule below.
Fantasy rule: Behead anything you think you've killed...Always confirm your kills if possible. If you didn't confirm the kill, don't be surprised when you see him/her/it walking down the street or crawling through your bedroom window.

The World's Funniest Joke:

Two hunters are out in the woods when one of them collapses. He doesn't seem to be breathing and his eyes are glazed. The other guy whips out his phone and calls the emergency services. He gasps, "My friend is dead! What can I do?". The operator says "Calm down. I can help. First, let's make sure he's dead." There is a silence, then a shot is heard. Back on the phone, the guy says "OK, now what?"

In Freeman's Mind, Gordon has explicitly stated he doesn't need to make confirmation kills. Apparently he's not at that stage of his life just yet.
In Panthera, they never stop to empty a few rounds into the corpse of their old master, even though they could only guess that he was really dead, and if he wasn't he'd be fine in five minutes.