Size changing

A little known fact, but Wasp is Soundwave's cousin.

Although scale has never exactly been a deep concern when it comes to Transformers, given that the series has featured F-15 jets not much larger than sports cars, it is not uncommon for certain Transformers to clearly and deliberately change size when transforming from one mode to the next. The methods employed for this startling alteration in physicality have differed from timeline to timeline, and have long been a heavily debated aspect of Cybertronian technology.

Examples

Note that many of the Transformers named here have also transformed at certain times without shrinking or enlarging, retaining an alternate mode to scale with their robot mode. It doesn't help mass-shifting logic though. If anything it only results in more questions.

Shrinking

Where does she keep it all?

The most famous examples of size-changing Transformers are Megatron, who becomes a pistol, and Soundwave and Blaster, who both become stereo cassette players. These Transformers visibly shrink as they transform, assuming one of two sizes — one that allows another Transformer to wield or operate them, and another, even smaller size that allows them to be transported in car-alts or used by humans.

Other shrinking Transformers include Reflector, Perceptor and the Mini-Cassettes.

Overkill's Transformers Universe bio notes that he has a defect in his transformation circuitry, which often results in him not being able to complete his transformation by not growing back to his robot mode's full size.

One of Deep Cover's abilities is being able to shrink to 1/40th his size for brief periods of time.

Shrinking into altmode is a property also shared by Animated Prowl and Prime Arcee. They both transform from motorcycles, which are about the size of a human, into full-sized Autobot warriors. In Prowl's case, he grows to be bigger than Bumblebee, who's a car (granted in "Animated" most of bumblebee's vehicle mass goes into foot size and Arcee's mass goes into leg length for acrobatics).

Enlarging

Conversely, Transformers have been known to grow in size when assuming their altmodes — the most prominent example is surely Astrotrain, whose space shuttle mode could become large enough to convey a whole contingent of Decepticon warriors, and even allow Devastator to form inside him. Similarly, Broadside transforms from a robot of roughly average size (occasionally depicted as somewhat tall, but never huge) into a jet and then into an entire aircraft carrier, of the type used to transport dozens of jets. Other Transformers that enlarge in such a manner also generally do so for the purposes of transporting others; they include Omega Supreme, Skyfire and Cosmos. Combiners are often larger in their combined form than their robot modes would otherwise indicate - in fact, in the episode "Chaos", Predaking is explicitly shown to enlarge after his combination is complete. In the original animated series many of the Transformers arguably enlarged or shrank in vehicle mode to a lesser extent, this is most notable among groups such as the Decepticon jets and minibots, whose altmodes could not possibly turn into robots that are the size they are depicted otherwise. Whether this was truly intended to indicate actual size changes, was merely "lazy animation", or was simply a stylistic choice designed to emphasise the awesome stature of robot-mode Cybertronians, is a matter of individual opinion.

Magnificus has a matter-enlarging scope, which he used to make Ga'mede fit in in the macroverse.

Implicit size changing

Mass displacement my boron compressor.

Transformers that act as transport for other Transformers often implicitly change size to do so. However, size changing is rarely explicitly depicted in these cases. Instead, the following method is used: A character such as Astrotrain transforms in-frame from robot to shuttle with no visible expansion of size relative to his surroundings. Cut. In the following shot his fellow Decepticons are shown running into frame, suddenly relatively tiny in stature so that they can board the shuttle. Although Astrotrain has not been shown to actually grow, one has to infer that this is more likely than that all his confederates have individually shrunk.

The same change-in-scale-via-implicit-size-changing is used with Omega Supreme and other characters used as transport. For example, in the episode "Make Tracks", Hoist, who is depicted as one of the larger Autobots in robot mode, is shown riding inside Huffer, a Minibot whose truck mode is usually depicted as being smaller than Optimus Prime's. So either Huffer is extremely large in that scene, or Hoist is suddenly the size of a human.

(The other explanation is that the animators simply hoped no one would notice the sudden change in scale. Since Transformers is usually targeted at kids, there's probably some truth to this.)

Pretenders

Although the original American cartoon did not feature any Pretenders, the Japanese-only continuity did, in their series Super-God Masterforce. Here the Pretenders did not have outer shells so much as ill-defined holistic transformations which explicitly involved size-changing, allowing the Autobots to convincingly pass themselves off as humans. Also, Autobot Pretenders' shells are able to perform size changing in the Super-God Masterforce manga. The Decepticons, by comparison, chose to retain their gigantic proportions when in Pretender-mode.

Although never depicted in any of their actual fiction, Dreamwave's More Than Meets The Eye encyclopedia stated that Pretender shells use shrinking technology to achieve the Masterforce-like capacity to pass the wearer off as a real human (or other small lifeform of choice). (Intriguingly, the profile also obliquely implies that Pretender technology would later lead to the development of the faux-organic beast modes of the Beast Era.)

Explanations

Although size-changing has been evident in Transformers from the very beginning, the original animated series and comic books never address the topic, and it was regarded as simply being the way of things. Fandom debate on the topic has seemingly inspired later fiction to offer varying explanations on how it functions.

Dreamwave

Dreamwave offered two explanations for size-changing within its continuity.

The first, to explain enlarging, was parts compression – the notion that the Transformers in question, such as Astrotrain and Broadside, had many dense layers of armor in robot mode, which then slid out, expanding to create a much larger, but less-strongly-armored vehicle mode. Fans have referred to this as the "origami Transformers" explanation, and it appeared in their More Than Meets The Eye encyclopedia.

The second explanation, to justify shrinking, was mass conversion. This method put it that Transformers like Soundwave were genetically endowed with the ability to transform not simply their bodies, but their entire molecular structure. This ability, not under their conscious control, only activates when they transform, shifting their atoms according to a pre-determined schematic.

IDW

File:Massdisplacement.jpg

Shrinky-dink.

IDW's Escalation sees Megatron employ a mass-displacement sequence, physically discarding a portion of his bodily mass to allow himself to shrink to a human-scaled pistol of appropriate weight and density. What with E equalling mc², the loss of this amount of mass (shunted to an undisclosed location in space and time) results in a volatile energy discharge, requiring bystanders to step away lest they be injured by the forces released - not that Megatron would care.

Due to the energy shortage (and seeming near-total depletion of Transformers' primary fuel source, Energon) caused by their war, mass displacement hasn't been commonplace for a very long time. Since it requires a huge amount of energy, the technology had practically vanished until the discovery of Ore-13 on Earth.

2007 movie

The creators of the 2007 live-action movie explicitly avoided including any Transformers who could change size, wishing to avoid the necessary suspension of disbelief. Therefore, any observed scale problems are genuine scale problems. (And there are a few, most notably human-sized Frenzy's head turning into a tiny cell phone.) That said, size-changing technology clearly exists in some form in the movie continuity, as Bumblebee somehow shrinks the AllSpark down to a manageable size and mass. Thus far, there's no evidence this trick can be applied to anything except the AllSpark.

Fandom explanations

Just when you thought you had it all figured out...

The issue of shrinking and enlarging was, in the early days of the online Transformers fandom, a frequently debated subject. The Transformers were clearly displacing their mass, to allow their shrunken forms to be operable – so where was that mass going? The postulated answer to this question was the invention of "subspace", the void of extradimensional space between realities. Subspace proved a handy answer to various other questions as well - see the concept's own article for details. IDW's "mass displacement" rationale essentially is the subspace explanation, without actually using the term.

And hey, if any of that doesn't grab you, a wizard did it.

Note

When you see a character's size is smaller than usual, well, it's just a technical issue.