The typical Crawls have a rotund, grey torso with a vent on their belly and a neckless red or orange head with insectoid mandibles and two large eyes. Possessing short limbs, they have a yellow crab-like pincer on one arm while the other wields a Bumper with a red background, blue center and yellow/white star in it.
Several changes were made to the Crawls' design in Sonic Rivals 2, Sonic the Hedgehog 4 and Sonic Generations, but their overall appearance has remained consistent.
Sonic the Hedgehog 2
Crawls first appeared in Sonic the Hedgehog 2 as the only enemies in Casino Night Zone. In gameplay, Crawls crawl slowly (hence their name) back and forth on routes. If the player tries to attack them from the front or above, the Crawls will hide under their shields which can bounce the player backwards while leaving the Crawls unharmed. The only way to destroy a Crawl is by hitting them with a Spin Attack from behind.
In the 16-bit version of Sonic the Hedgehog Spinball, a single Crawl appears behind two Cluckers on the pinball table of the fourth Bonus Stage, named "Clucker's Defense". In this bonus stage, the player has to destroy the Crawl using pinballs. Each hit earns the player 1,000 points.
When targeting the Crawl, it is impossible to hit it up front as its shield will only bounce the pinballs back. Instead, the player must attack the Crawl from the lateral sides multiple times until it loses its shield. It can then be destroyed with the next hit. Oddly enough, this Crawl does not have an animal inside it.
Sonic Rivals 2
In Sonic Rivals 2, a Badnik similar to the Crawl (named Guardon Crab) appears. These Badniks were created by Dr. Eggman, but Dr. Eggman Nega managed to take control of them. These Guardon Crabs appear in Neon Palace Zone and Chaotic Inferno Zone. Though this Badnik has the same attack pattern like the Crawl, it can be destroyed from any angle, regardless of its shield. The collectible card for the Guardon Crab can be obtained by completing Mystic Haunt Zone Act 2 with an S rank.
In the Nintendo 3DS version of Sonic Generations, Crawls appear in Casino Night Zone. In this game, the Crawls seemingly retain their attack patterns from Sonic the Hedgehog 2, but they do not have animals inside of them. In Casino Night Zone Act 2, Crawls can appear in lines which Sonic can plow through with the Boost despite their shields.
Sonic Lost World
Crawls appears in both versions of Sonic Lost World. During the game, the Crawls and the other Badniks got hijacked by the Deadly Six. Here, the Crawls retain their original look from Sonic the Hedgehog 2, with the exception of grey legs and a yellow orb on their armor.
In the Wii U version of the game, Crawls appear in Frozen Factory Zone 3, Silent Forest Zone 4 and Lava Mountain Zone 3. Like in earlier games, the player cannot attack the Crawls from the front, so they must hit them from behind where they have no protection. In the Nintendo 3DS version of the game, Crawls appear in Sky Road Zone 1-2. In this version, the Crawls can in addition fire projectile waves at the player, similar to the Somersault Kick. Crawls will also spin around once while their shields and claws are relaxed. If the player can intercept a Crawl's projectile wave with the Somersault Kick at the right time, the attack gets canceled out and the Crawl will be stunned at the same time, leaving it open to attacks.
Powers and abilities
Crawls can defend themselves using their shields, which can bounce back the player as if they are hitting a Bumper. These Badniks do not have any conventional attacks though, and instead rely on walking slowly into their opponents. However, their fatal flaw are their rear which have no form of protection.
In the Sonic the Comic series published by Fleetway Editions, the Rollers are a part of Dr. Robotnik's Badnik army, although they only appeared a few times during the series' run. Depending on the artist, the Crawls' design would be altered slightly each time.
There are alternative sprites in the Simon Wai prototype of Sonic the Hedgehog 2 that exist inside of the game's coding. These sprites depict the Crawl in different position and holding its shield in the lateral directions, which it does not do this in final version. Its pincer is also depicted as grey.
The Crawls' pincers are also miscolored grey in the mini-game of Sonic the Hedgehog Spinball.