How do I make my character look like she's moving in and out?

Heya, I'm the only dev of an Point and Click RPG that's like Sam and Max mixed with Mario and Luigi.

For a while, my character (Who's size is set to 158 x 386) looked like she couldn't move halfway through the room vertically. I had now fixed the visual bug but now she looks too big.

You see, I use an event that's basically "EVERY TICK: Terry| Set scale Terry.Y÷850"

The sprite I use as the walkable floor is at max 373 at height at this point.

Soo.. Can somebody help me get my girl into the right size? (I might make a feature based on this mishap. XD)