Vertical Propellers

'''The vertical propellers are a variation of the propeller. They are formed of multiple exceptionally long blades of glass, which can (sometimes) self-destruct upon contact with the ground, or loose balls and glass shards. They are found in Zen Mode and Checkpoint 6, and can sometimes be dodged.'''

Like this:

This one is used in zen mode

To differentiate between normal (horizontal) propellers and vertical propellers, vertical propellers look longer, and horizontal ones look shorter.