I'm a brand new creator as of this game, and I think this (read title) would be a good thing to have for Swoop levels. I'm not sure how I would make this.
If someone's already made this, please tell me. Give me some tips, too, if you got any. I'm pretty much brand new to this stuff.

Here is what you have to do:

Create a sackbot. Bring up the sackbot's menu and make some changes(swoop model, costume) and close.

Then place a controllinator in the sackbot's curcuitboard(bring it up by pressing R1 on the sackbot)

In the controlinator menu, change the controlinator type to Reciever and select "controlled by nearest player."

Then, in the tools menu, select the in/out mover under Movers and place two on the circuit.

Map the controllinator buttons to the movers. I would suggest L1 and L2.

Select 1 mover and set the input action to move out once. Vice versa for the other other one.

Now, go to global settings and on the top of the characters page, select "Create custom character" a box will appear. Select your sackbot and press X.

Your sackbot should appear under My Characters. Select it , and you will turn into swoop.

You should now be able to move between layers in game.

Have fun. If you have any problems just tell me.

Yay! Thanks for responding!
What do you mean by, "Select 1 mover and set the input action to move out once. Vice versa for the other other one"? Do you mean select the input wire thing on one button and connect it to one in/out thing, and connect the output button to the other in/out thing for the other button?
Can you help me understand what the input and output buttons even are? They confuse me...

Here's it a little simpler:
1. Put down a sackbot.
2. Change its costume to Swoop or a desired outfit.
3. Place a Controlinator on its circuit board and set its type to Receiver.
3. Open up the Controlinator's circuit board, and place two In/Out Movers (found in tools bag) on it.
4. Tweak one of the movers to go in once and the other to go out once.
5. Set a buttons to change layers. For example, you can connect the L1 button output (output is the wire that comes out of it) to the mover that goes in once, and the R1 button output to the mover that goes out once. That means that pressing L1 will make Swoop go back a layer, and pressing R1 will make Swoop go forward a layer.
6. Two Ways:
*You can now add the sackbot as a character to your level by going to the Global Settings menu, going to the Character page, selecting "Create Custom Character", select the sackbot, and the sackbot is now wearable.
*You can use a remote Controlinator to control the sackbot, too. Place down another Controlinator in a random spot in the level, set its type to Sender (or something similar-I forget the exact name), making sure that it uses the same frequency (color) as the one on the sackbot. You can then use it to control the sackbot.

Or you could skip the whole sackbot thing and use the Broadcast microchip here

What do you mean by the character being wearable? And what's the difference between input and output in general?
Ooh, and what does nerd_dog mean by a broadcast microchip?
(Sorry about all the questions, ! I'm new to this stuff!)

First of all you should know what input and output is, men ;-; Input it's thing when we insert something and output it's the thing that goes out of something (for example) - a cable.

Broadcast microchip does exacly the same as in its name. It broadcast. For example: Place it on the floor made of any material. Place in it a Gameplay Tweaker and set movement to 200, then configure a brdcst. microchip to activate at touch. So: If you step on that floor, your movement speed will increase to 200%.

- The microchip sends/copies itselfs into player (or anything - depends on how you will tweak the microchip) who stands on the floor.
You always can make a "zone" from hologram and place microchip on it so it will appear on anyone standing there.

Ehkm, finally wearable character - Basiclly when you are creating level you can choose what character will be default. But they doesn't end on swoop, toggle, oddsock or sackboy! You can capture your own sackbots (let's say - a sackboy with custom costume of yours and with superpowers like for example: fire breathing).

Hope I helped, good luck in creating levels;
ah and one little WARNING when creating make saves for 10-15 minutes because LBP3 likes to crash while diggin in logic

BTW any idea why my quest are appearing while creative, but when i test levels it seems that all quest things aren't appearing at all :/

And I thought I was being somewhat clever with my idea. My problem was really easy to solve... guess I got a lot to learn.
So you always have to place broadcast chips on the floor? Or can you place them anywhere?

You always can make a "zone" from hologram (and set light to 0) and place microchip on it so it will appear on anyone standing in it. If you will need more help add me on psn and i'll solve it for ya!
Peace out!