Metronomic Mook Massacre

One way for a character to deliver a severe beatdown on an opponent is to pick said opponent up (usually by the feet) and slam him left-right-left-right overhead into the ground. It's generally an indication that either the character doing the slamming is very strong, or very very angry. This can be played for even greater effect if the character doing the slamming is either very small or, in normal circumstances, shouldn't have that kind of strength at all.

Examples of Metronomic Mook Massacre include:

Advertising

The spider in this Mentos commercial does it to a full-grown man.

Anime & Manga

An Indigo League episode of the Pokémon anime has Ash's Bulbasaur get beaten up by a Bellsprout in this manner.

Comics

Asterix himself has been known to do it, though Obelix uses it more frequently.

Films -- Animation

Kung Fu Panda - Po is beaten by Mantis using this style of beatdown.

Films -- Live Action

The Hulk does this to Loki in The Avengers.

Video Games

Killer Instinct: Galacius does this.
In Marvel vs. Capcom 3, Super Skrull combines this with his Rubber Man and Super Strength powers.
Teenage Mutant Ninja Turtles Turtles in Time on the SNES has an attack matching the trope.
In Super Smash Bros., Samus can do this with her up grapple attack.
In Street Fighter, T.Hawk has this as his second ultra combo.
In Earthworm Jim, a tiny cat mook will do this to Jim if he approaches it. Then again, it's a really fast way to skip parts of the level if you have enough energy to endure it.
Sonic Unleashed: Sonic the Werehog can do this to some of the bigger mooks once he gets his elasticated hands on them.
The Tank does this to some zombies in the intro movie of Left 4 Dead.

Western Animation

The Atom Ant Show: The tiny Atom Ant hands out pounding in this style.
Powerpuff Girls
Droopy Dog: Droopy can do this, but only if you make him angry.
The Flintstones: Bamm Bamm BAM-BAM-BAM!
The Ant and the Aardvark has this happen after the ant took some vitamins.
Dave the Barbarian has Amoeba wrestling.
Kim Possible: The ninja toddler Hana does this to Monkey Fist.
Darkwing Duck: Stegmutt is talked into pretending that Darkwing is on fire and "putting him out".
The Last Days of Foxhound: How Liquid defeats the cyborg ninja for the second time ( after being impaled by his sword, no less).
Looney Tunes: The adorable little Chicken Hawk does this to Foghorn Leghorn Once an Episode.
There was a Merrie Melodies where a "strongman" flea from a flea circus did this to a big dog who was picking on the little dog the flea was vacationing on.
Tom and Jerry: Jerry did this to Tom once when he (Jerry) got super-strength.
In Wakfu, this happens to Sadlygrove during his fight against the Dragon-Pig. It would have gone for even longer if Evangelyne hadn't courageously bitten the Dragon-Pig's tail, distracting the monster.