The Fighting Polygon Team (Dummy Corps. or Mysterious Small Fry Enemy Corps., 謎のザコ敵軍団 in Japan) was a team of purple polyhedrons, who only appear in the original Super Smash Bros.. They were modeled on the playable characters in the game. They appear only in the single player mode, in Race to the Finish and the Fighting Polygon Team [vs.30] battle, the two stages prior to the Master Hand battle.
Donkey Kong looks the most like the normal character out of all of the Polygons. Like Donkey Kong, this one is bigger than the others and has a masculine frame.
Captain Falcon, Link, Fox, and Samus all have humanoid Polygons. The differences between them are that Samus has a spike for an arm that mimics the arm cannon, The Link Polygon has a spike of its own to mimic a sword, and the Fox Polygon has a tail.
Mario, Luigi, and Ness all look a lot like elves, thus making them difficult to tell apart. The Ness Polygon looks like it is wearing shorts, and the Luigi one is slightly taller than the Mario one. An easier way to distinguish them is to look at their movesets. Mario flexes his arms and the one who does a slide attack. Luigi bends his legs and who flail punches when doing a dash move. And Ness swings his arms, a star always appear each time he jumps, and swings his yo-yo.
Yoshi has a very pointed head and sharp teeth, making the Polygon look much more like a real dinosaur (in particular, a Deinonychus or Velociraptor), and much more threatening, than normal Yoshi, who has a large, bulbous snout and whose teeth are not normally visible.
Kirby looks like a short snowman made up of three different sized shapes, with stubby arms and feet. This Polygon has the same number of jumps as normal Kirby.
Jigglypuff looks like a big, round rock with a spike in the middle of its forehead, mimicking the tuft of hair. This one is often confused with the Kirby Polygon. This Polygon, like the Kirby Polygon, has the same number of jumps as normal Jigglypuff.
Pikachu looks a lot more like a mouse than normal Pikachu, with wider ears and a spike for a tail instead of a lightning bolt (which is appropriate considering the fact that Pikachu is a Mouse-Pokémon), making the Polygon closely resemble a Sandshrew.
Fighting Polygon Team [vs.30]
In this stage the player must defeat a team of thirty Polygons, fighting at most three at any one time. The only way to play as these fighters is through via hacking with a GameShark. Instead of being fought in a given order, all Polygons, including those modelled on characters that haven't yet been unlocked, have an equal chance (1/12) of being the next one to appear. In general, they are relatively passive on all difficulties, spending most of their time just walking around the various platforms of the stage, rarely following the player, and very rarely using attacks. They are fairly light, do little damage or knockback, have no B-button attacks, and will not grab, though they can, and will, pick up items. Normally, they will use a throwing item as soon as they have picked it up, instead of making any sort of tactical decision. They can use battering items, though, even on the hardest difficulty setting, they are not as effective with them as a high-level CPU player in a normal game. Due to their low weight, they can usually be defeated in a single blow, but the Polygons get heavier and stronger at higher difficulty levels, and at the highest difficulty level the Polygons approach the weight and strength of normal opponents, though they are still relatively easy to KO.
Race to the Finish
The aim of Race to the Finish is to reach the door at the end of the level within a set time limit, avoiding obstacles that try to slow you down. The Polygons are obstacles to be avoided, and slow the player down by attacking them, but they cannot be defeated, nor can they KO the player, as the stage is fully enclosed (they can however be ko'd if you knock their percetage high enough that they will be sent through the barrier too quick to be stopped, though this percentage is about 400 and requires more time than the stage allows). They are much more aggressive on this stage, chasing the player as far as possible, and attacking whenever they are within reach.
Their shape and name is likely an exaggeration of the N64's polygon-like graphics.