How to make a character whose size you can control?

Hi, for a college project I need to make a character whose size the player can control so that they can successfully navigate an area. I was wonder how to do this? Would I need to animate this in my modelling program first or would it be coding to alter the scale in unity? And how would I make it stop growing at a maximum size or stop shrinking? Any help with coding would be very much appreciated.

maybe you could use this?

you could also clamp the minimum and maximum size with clamp.

or at least thats how id do it, everyones different. Good luck!