*. Tachikoma

Tachikoma's are the main Robots used by the team of protagonists of Ghost in the Shell. This team is none other then Public Security Section 9. Tachikoma's are only seen in the TV Anime verison of GitS, Stand Alone Complex (SAC). Within the series, the Tachikoma's are a type of robot that is normally called an "AI walker Tank" because that's exactly what they are. Their walking tanks with AI that are capable of speech, as they act childish, curious, joyful but when it comes to the job, they know what they need to do. The size of a Sedan, Tachikomas can either walk using their four legs, or roll around like a mother fucker due to their legs having omni-directional wheels. Not only that, Tachikoma's can jump like a mother fucking jumping spider, walk along walls, and have adhesive string launchers (a.k.a. Web shooters). Did I forget to mention that they have thermoptic camouflage?

Normally, these little guys are equipped with a .62x51mm light machine gun built into the right arm, a 50 mm grenade in the "snout", but can be replaced by a six-barreled 12.7x99mm Gatling gun.

TL;DR version: The reason why Tachikoma's are in the Special Tier is because they are WALKING TANKS that can roll along basically ANY surface, jump like the mother fucking Fist Of The North Star, turn invisible, all while they shooting shit up with a machine gun and whatever the fuck you attach to the front, and are technically the comedic relief of the show. Oh and you see dat ass on the back, that's the glove compartment which can fit a whole person. A person who is most likely a trained anti-terrorist who jumps off helicopters to shoot the terrorists like a mother fucker. Did I forget to mention that the helicopter-jumping person is a cyborg? A female cyborg?

Note: Tachikoma's are originally based on the GitS manga mecha named Fuchikoma. Due some sort of copyright issues with using the Uchikoma in the TV anime, the creator face palmed and designed the Tachikoma, which is essentially the same thing in terms of abilities and role.