Panel 1:
Tile pulls on the right panel border, which arcs toward her.
Caption: Our borders today are extra springy.

Panel 2:
Tile releases the border which wobbles as it bounces back.
Caption: Boing!

Panel 3:
The right panel border disconnects from the top corner, as the force of the bounce proved too much, and Tile watches as it begins to fall like a rope.
Caption: Oops.

Panel 4:
Instead of continuing to fall, the former panel border grows a small snake head at the top which lunges toward Tile. Tile flees to the left.
Caption: Ahh, it's a snake!