How to get character to transition from foreground to background?

So I have a 3D side scroller-ish level that is split into 5 vertical parts. I start from the front left and go all the way to the right til I reach a checkpoint then the character is suppose to walk towards the background(opposite of the camera) then starts the second part of the level and walks all the way to the right til I reach a checkpoint and repeat til I make it to the finish line. Now my issue is that I don’t know how to get my character to walk to the background once I reach the checkpoint. What I am asking for is how can I make a short (2sec) animation that shows the character walking to the background which is the next part of the level. Similar to the Super Mario animation after he finishes a level he slides down the pole and walks into a castle/pipe and enters it. I just want to know how to make the entering castle part then give the player control of the character again once they make it to the next part of the level.

Here is my solution, haven’t try it out yet, but you may want to use the same trick as Resident Evil games back in the 90s, to trick the player into believe that the character is far away from the camera, they scale their character size to a smaller one, and vice versa. Make your camera stay put at a location, rotate your character so that his back facing toward the camera, then begin the walking animation and over time, slowly re-scale your character to smaller scale. You can do the same when you want your character to walk out of the background, but this time, scale your character to bigger scale.