WARNING: The following contains spoilers for Episode 37 of That Time I Got Reincarnated as a Slime, now streaming on Crunchyroll.
Rimuru Tempest's isekai adventure began in a crystal-filled cave, but he was not alone. Veldora the storm dragon was imprisoned there for centuries after losing a battle to the masked Hero and had no chance of escape. So after giving Rimuru a name, Veldora allowed himself to be absorbed by his comrade's Predator skill.
Throughout Season 1 of Reincarnated as a Slime, Veldora spent all his time inside Rimuru's belly, simply observing the world through his human host and playing shogi with his sole roommate. But now -- in the second cour of Season 2 -- Rimuru has become a True Demon Lord, he gains the strength to give the mighty Veldora a new body, and the storm dragon couldn't help but turn it into a pop culture reference.
In Episode 37 of Reincarnated as a Slime, Rimuru makes a second body for Veldora to inhabit, which assumes the form of a tall, musclebound man with dazzling blond hair and lightly tanned skin. Delighted to have a physical body once again, he speeds around the cave as though teleporting, throwing rapid punches and kicks to test out his strength. Once outside, Rimuru advises Veldora to tone down this new power, and the reborn dragon complies. He adopts a familiar stance, cries out in the effort of suppressing his aura, and envelops himself in a fierce yellow torrent of energy -- all while his blond hair stands upright. This sight definitely looks familiar to Rimuru's eyes.
Sure enough, Reincarnated as a Slime's Goku-style moment is a remarkable pop culture reference to Dragon Ball, and it isn't a coincidence in-world either. Veldora, having had access to countless issues of manga magazines while inside Rimuru's belly, knew what he was doing. He was familiar with Goku and the concept of Super Saiyans, so he decided to have some fun imitating one while testing his new humanoid body.
Veldora has a lot of fun mimicking Goku -- complete with a Super Saiyan form -- but he has the discretion to not take it too far. He makes a few verbal references to the source material and performs his power-up, then resumes acting like himself. Even Veldora knows it's silly to act like a Goku knockoff the entire time, and no doubt Reincarnated as a Slime's creators know the joke would go stale quickly if he'd kept it up for more than a single scene. This show has a good sense of meta-humor but also exercises enough restraint to deliver a single punchline before withdrawing to resume its own storyline.
The storm dragon is loud and gung-ho when meeting the Tempest citizens, enjoying the attention when all the monsters recognize him and bow down to him. His ensuing enthusiasm and loud speech are refreshingly true to himself, rather than imitating someone else.
Veldora's rebirth in human form is a serious novelty and a big step forward for the character, so Reincarnated as a Slime Episode 37 does well not to waste that opportunity by simply turning him into a Goku cosplayer. Still, one or two more Super Saiyan jokes in the future might be appreciated -- if Veldora has the discretion to time them correctly. He certainly has enough source material to draw from.