Identical Panel Gag

In a comic, one way to produce a humorous suspense or simply signal that something doesn't exactly go as expected in a conversation, is to show several copies of the same panel successively.

The dialogue may go on and external details may change, but the characters, or at least one of them, will not move an inch. Their position and expression will be a literal copy and paste.

This conveys a feeling of stoic disbelief, utter cluelessness or mere indifference from one or more of them, from which Hilarity Ensues. The conversation where this happens usually doesn't go anywhere.

In comic strips, the Identical Panel Gag will either precede the punchline or be the punchline itself. In some cases, the entire strip can even be made like this.

A variant can be to draw identical panels not successively but separated by different panels, by pages, or even by volumes for a Brick Joke effect.

Beat Panels can resort to it. Some Cut and Paste Comics rely entirely on this, although it can be out of laziness or to save time. This trope is for when the repetition is used deliberately for comic effect.

Examples of Identical Panel Gag include:

Advertising

Done for this glue ad. The glue is so strong that there is no difference between before you broke the vase and after you fix it.

Anime and Manga

Used in Bleach when Ichigo wants to transform into a Shinigami to go and save Rukia... before realizing he has no way to do so (Rukia has the transforming glove and the Soul Candy is inside Kon).
- Also invoked during Hiyori's introduction to Orihime and Sado, where she smacks Shinji each time he interrupts her. Identical panels are used to highlight Shinji's worsening condition as well as Chad and Orihime's reaction.
Done in D Gray Man during the brief flashback with Mana. A dialogue between a clown-hating Bratty Half-Pint and a clown who doesn't exactly have all his head can lead to this.
In Code Breaker, Kanda suggets to feed a puppy with… onions. And sake. (see the trope image)
The first pages of the two fights between Aoki and Papaya in Hajime no Ippo both have a rigorously identical panel layout and an identical pose for Aoki. So are the pages where Aoki takes the "Coconut Punch". The two fights are dozens of chapters apart, making it doubly hilarious when you realize that.
In the later chapters of Dragon Ball, Trunks and Goten repeatedly attempt fusion with varying results. The reaction panels are the exact same to the point that Kuririn calls Akira Toriyama himself out on it.
Used in Wizard's Soul, perhaps not for comedy, but to just emphasize the main character's cruel, 20 turn, Cherry Tapping of her opponent. 18 straight almost identical panels of the main character attacking with the weakest creature possible with the main difference between the panels being the opponent's face expression and to some extent the opponent's thought bubble (after the 4th one, they are all "...").

Comic Books

One page of Hero Squared was a nine-panel grid of Milo in the exact same pose.
Hilariously lampshaded in this page of Invincible featuring a comic book artist talking about reusing panels.

Newspaper Comics

There's a Calvin and Hobbes strip where Calvin is telling Hobbes about his grandfather, who complains that modern comic strips are "nothing but a bunch of xeroxed talking heads". Every panel in the strip is the same two-shot of Calvin and Hobbes, with only the speech bubbles changing. (Although if I recall correctly, on closer inspection, there are enough tiny differences to show that each "identical" panel was actually drawn separately.)
This happens inadvertently in Garfield Minus Garfield strips since Garfield is removed from the panels. Granted, when this happens normally, it's a conscious decision to reuse valuable panel space.

Web Comics

The VG Cats love to do this. This notably happens just before Aeris's Atomic F-Bomb.
One series of panels in Sluggy Freelance shows someone demonstrating what it would be like to get stuck in timeless space. It's a few dozen frames of the character not moving. One in the middle shows him looking at the camera.
Cyanide and Happiness does this in nearly every single comic.