In the Super Mario Odyssey video game, early on in the play time Mario is able to "capture" a frog with his new companion Cappy. This game mechanic works on various creatures throughout the game by simply throwing Cappy onto the creature which enables Mario (and the player) to gain the creatures' abilities.
After the first capture of the aforementioned frog a cut scene takes place. During this scene Mario is transported through what seems to be a liquid (we see air bubbles) but also seems to be some sort of space-time portal. Mario is seen to be aware of this travel aspect and is shown as a full body. Mario then wakes up and open his eyes as the frog.
Is there any explanation on to what "in-universe" is happening? Is Mario's whole body being transported into the creatures brain, is it a "mind meld", is there some form of transfiguration?
I'm ideally looking for something released from Nintendo, possibly a walkthrough manual or companion book/comic.