This just fits on so many levels; both Rainbow and The Flash are known for their super-speed. Why Pinkie was chosen to be Filisecond (Who was based on Flash) in Power Ponies and not Rainbow I will never know.
Also, RD’s eyes in the first pic look a bit derpy.
Same reason Shy was a Hulk expy.
Also, RD’s eyes in the first pic look a bit derpy.
Edited