Or, you know, it causes her mane and tail to chip off slightly, causing the rainbow effect as the light passes through the ring of keratin dust.

@EvilDarkForcesRus  
hmm….“In the magical land of Equestria” you may be on to something.

My headcanon states something, but I shouldn’t say it on a safe image.

@Dr Outback  
my headcanon is that its not ponies that are magical, but the entire plannet is, the different type of ponies just have different means of channeling the magic in the atmosphere

@Background Pony #4A5E
 
 
My head cannon for that is that she has a great grandmother that was a changeling (comes into play in one of my stories I have in my head but haven’t put on paper) and her power is a form of the hive link manifesting in a (mostly) pegasis pony. Escentially she sends out a pair of magical threads/links from her mind conducted out her eyes to inject her will into others.
 
Also though this head cannon came way before “Bats” it could be used to explain how there was a backfeed off the bats and back into her.

@Millennial Dan  
Her father was a cockatrice.
 
Actually I can’t explain that one. I just figured it was a thing she naturally had anyway.

@Background Pony #4441  
I find Cutie Marks to be more Biological than magical

@Background Pony #4A5E  
The Stare™ is also sort of magic-based, so where did that come from?

But how fast would she have to travel in order to create a shock wave that powerful?

Maybe it creates water droplets or something that, in turn, create a rainbow? I don’t fucking know, I’m not a rainbow scientist.

The first rainboom Dashie did vibrated in just the right way to give Pinkie Pie her superpowers, or whatever you would call the magic she so often displays.
 
That’s my headcanon and I’m sticking to it.

@Gizoid101  
Kind of, but all fiction follows an internal logic. This wasn’t meant to be debated hard on, because in the end we’re discussing magic.

Actually my head cannon has a similar system, though it is that the magic containing layer of space in their world (not that ours has one…) vibrates in a similair wave to audible sound.
 
Also all living beings (especially higher intelegent or magical) have a net feild around them eminating from their life force and this interacts with the ambient magic layers. Thus when a magic being such as Rainbow Dash breaks the audible sound barrier they also cause a shock wave by their life force simultaniously passing through it at the same rate. When this happens the large magic wave/build up washes over the beings life force core and intermingles with the life source vibration of that individual thus causing a rapid upsurge in the individuals powers and casting a wave marked by the individuals signature vibration (cutie mark).
 
Yeah, I know its over anylization but its just how my brain works and is fun for me. shrug

I remember that some dude told me that arguing science with magical talking ponies is stupid.

@Dr Outback  
The entire planet is magic. Cutie Mark are evidence that ponies are magic even if not all of them can manipulate magic. It’s not much of a stretch.

There’s magic in the atmosphere? That makes sense I guess

@gallagher117  
I suppose?

Sooo… it’s like magical cavitation then?