Charcoal, 1010 9 bytes
↓E⮌θ◧ι⊕‽Lθ↑Eθ◧ι⊕‽Lθ
Try it online!Try it online! Link is to verbose version of code. Edit: Saved 1 byte thanks to @ASCII-only. Explanation:
θ Input string
⮌ Reversed
E Map over characters
θ Input string
L Length
‽ Random value
⊕ Incremented
ι Current character
◧ Padded to length
↓↑ Print rotated
InsteadAs ASCII-only points out, you can move the letters randomly up instead of reversing and rotatingdown for the output cansame effect (except that there might be printedextra white space at the bottom rather than the top). Printing an array of characters upwards is equivalent to printing a string normally and reflected afterwards for, so the same byte countpadding then just offsets each character vertically by a random amount.