GIGANTAMAX GENGAR

See, this is another one that technically just gets a whole lot bigger, but just by sinking into the ground and yawning its mouth, it creates a very striking look compared to its base, giving the impression of some terrifying carnival funhouse ride or inflatable bouncy castle. They still missed some opportunities here, however; remember the third eye on Mega-gengar? What if you could see that blinking in the back of this form's throat, or something?

We haven't been talking about the signature move of each Gigantamax form, unfortunately, because I don't think they add all that much for review purposes. For instance, as long as Gengar knows a damaging ghost-type move, it will become Gigantamax Gengar's "G-Max Terror," which inflicts damage but then traps the opponent. It does at least tie in to its "lore" in an interesting way: Gigantagengar's mouth is said to be a gateway to the afterlife, and you can hear the sound of your loved ones calling you from within. Spookular!

I don't want to seem biased by the mere fact that this is a ghost type, but I think this demonstrates how easy it can be to make a giant-size Pokemon stand out more from its regular-size incarnation, even if you don't change too much of its actual anatomy. Presumably this has all the features of a regular Gengar, it's just phased down into the earth.