This is where mecha, robots, or anything similar have lower legs and forearms bigger than the corresponding thighs and upper arms, as if they had giant bracers and boots on, or bell-bottom pants from The '70s.
There's a few various reasons for this trope. One of the most common is the prevalence of robots with Rocket Boots or various arm mounted weaponry. Another reason is the prevalence of Shoulders of Doom or hip-plates on many robots, whose great size leaves less room for the upper arms and thighs respectively, while the forearms and lower legs are free to look bulkier. This can be accentuated further by a Mecha Expansion Pack, where the extremities are free to be armored up while the more heavily-jointed shoulders and hips need to be unobstructed. The added width also makes for a more combat-ready look, a punch thrown with forearms like that looks a lot more painful as opposed to more normal proportions.
And from an artistic standpoint, it can either come across as a convenient or a lazy design choice if drawing hands and feet comes of as time-consuming without covering them. Conic limbs also provide a sleek look if you're tired of stock boxy limbs. Alternatively, it can also convey stability; indeed, some Mecha drawing guides recommend making the bottom bigger than the top for precisely this reason. If there are toys based on the robot (or, alternatively, if the robot is based on a toy), then that artistic stability can double as actual real-world stability.
Contrast Top-Heavy Guy whose overall body is disproportionate and Creepily Long Arms for arms that are unusually long, compare Chicken Walker for another popular form of Robotic Legs. See also Fingerless Hands, which is the organic version of this.
Examples:
- In Astro Boy, many of the male robots have thick legs and forearms. Astro himself is an example if you count his boots. Epsilon who is a female robot also has them and still looks feminine in them since hers resemble arm warmers/leg warmers.
- Most of the Mirage series and related mechs in The Five Star Stories have noticeably heavy lower legs and long, flat feet due to using a twin-engine system with their main "ezlazer external combustion system" power plants mounted there, although many others have absurdly thin legs that couldn't possibly support their weight without sophisticated auto-balancers and probably some kind of limited gravity control thanks to having their entire reactor contained within the torso.
- The classic Gundam is a good example. Its lower legs are notably larger and more complex than the upper legs, it's less noticeable but still there with the arms. Some of the robots were designed to be more bottom-heavy, i.e., to shift their gravity center lower; most notably, the Dom has massive lower legs and feet with the justification that it has jets built into them that allow it to hover at high speeds over the surface of the Earth.
- In Mazinger Z, the titular mecha has these gauntlet/greaves thing going on its arms and legs. So do its successors, Great Mazinger and UFO Robo Grendizer.
- In One Piece, Franky the cyborg has big, inflated forearms which become even bigger and boxy after the Time Skip. Justified in that he puts many things in there, such as ammunition, a long chain, a shield, and a box of tools.
- The Ingrams in Patlabor are a strong example, having extremely large lower legs, the right one containing a compartment for storing a scaled-up revolver, and short, minimalistic thighs. This is explicitly in the interest of keeping their centre of gravity low so they don't tip over, which is the primary design concern with a humanoid mech that is two stories tall and meant to operate in an urban environment.
- All three Robot Romance Trilogy animes have these. Voltes V, Daimos, Combattler V all have forearms and legs that are armored with armlets and greaves.
- Gustus from Planet Heroes has absolutely massive lower legs and feet, but very skinny upper legs. This design decision was likely made so his action figure could stand upright, as he's the largest Planet Hero and his design would be comically top-heavy otherwise.
- Transformers: The majority are examples, often with Kibble attached to their lower arms, while upper arm Kibble usually turns into Shoulders of Doom detached from the arm. In toys with this, it's required since it's literally impossible to have the upper arm bigger, if the shoulder pad and upper arm are supposed to be flush with the lower arm when transformed. Similarly, many toys have larger lower legs than upper legs due to it being common for the toy's lower legs to fold over their upper legs in vehicle mode. The lower legs are usually incorporated into the toy's vehicle mode appearance, while the upper legs wind up being internal.
- Some of the 'Mechs of BattleTech are designed this way: many of the early designs which were drawn from anime influences feature large lower legs or forearms with smaller upper arms or thighs (for instance, the Crusader
). The most blatant offender probably being the Thunder. It doesn't have feet so much as it has very large shins that it just happens to walk on.
- While this is a purely cosmetic choice in the tabletop game, when translated into the real-time FPS combat of the MechWarrior series, these designs can become a huge liability given they're a much bigger target. The Crusader in particular tends to show up earlier in the fifth game than other 'mechs in its weight class because of how easily it goes down to Knee-capping.
- Warhammer 40,000: Many types of Humongous Mecha used by the Imperium of Man have some degree of this trope, with the most prevalent example being the Reaver Titan.◊
- Mega Man (Classic): Mega Man is more notable in artwork than in games but it's there in both. In some cases, his lower legs and forearms might be twice as thick as the arms attached, which usually look like blue tights. The same goes for most other Robot Masters, including Mega Man's brother Proto Man. When unarmored as Rock Light, Mega Man's limbs are of normal thickness.
- Mighty No. 9, the Spiritual Successor of Mega Man, naturally has these for its robot designs. Beck, Mighty No. 1, and Mighty No. 5 have large forelegs. Mighty No. 4 has large forearms.
- Many of the robotic characters from Sonic the Hedgehog heavily feature this design. Notable examples include almost the entire E-Series robots, especially E-102 Gamma and E-123 Omega, Emerl, Gemerl and the Gizoids, Metal Sonic (most prominently in his transformed state in Sonic Heroes), and Johnny from Sonic Rush Adventure.
- Murder Drones: N's legs, while still having feet, are designed like this. Presumably that's how all male disassemble drones' legs look, though N is the only one we ever see. All other drones either have pointed tips for feet, In the case of female disassembly drones, or thin, noodly limbs for regular worker drones.
- Schlock Mercenary: Lieutenant Foxworthy temporarily becomes a bell-bottomed Cyborg after an explosion severs her legs. The field hospital has a roboticist with spare Powered Armor parts but no body-part printer, so she spends some time with feet larger than her torso.
Foxworthy: I'm tall.
- Green Lantern: The Animated Series:
- In the episode "Steam Lantern", Duke Nigel's mechanoids are designed with this style in mind.
- Other more Downplayed examples include the Anti-monitor and Aya, whose limbs are only slightly larger at the ends.
- The Manhunters avert this, having more normal proportions.
- Megas XLR: Megas, the Glorft mechs, and pretty much all of the humanoid mechs fall under this trope.
- My Life as a Teenage Robot shows Jenny with uniform hose-style arms, but she has bell bottom legs with no feet.
- In Romie-0 and Julie-8, Romie-0's legs are designed this way.
- Samurai Jack: The Mondo Bot's hands and feet are proportionally very large but has comparatively skinny upper arms and thighs, this actually proves to be a massive design flaw as after Jack has merged with a magic stone giant he easily snaps his arms and legs with a single chop.
- The high-tech gem Peridot from Steven Universe has arms and legs that flare out from the knees and elbows like bell-bottoms and flared sleeves. When she joins up with the Crystal Gems in season two, it's revealed that these parts of her limbs are actually removable robotic extensions and not actually part of her real body, which is much smaller and has normal humanoid hands and fingers.
- Teenage Mutant Ninja Turtles (2003) has Professor Honeycutt, a.k.a. The Fugitoid, who falls cleanly under this.
- Transformers: EarthSpark: Nightshade's legs are like this.