Spoiler
 
Pinkie used too much hairspray on her hair and went to school during winter on a cold morning.
 
As a result her whole hair turned into solid ice and she was now able to pop the caps off bottles easily without any problems whatsoever.
 
However, moments after this scene was filmed Derpy Hooves ran right into Pinkie Pie by mistake and knocked her to the floor and Pinkie hit her forehead hard on the gym floor causing her whole hair to shatter into bits, leaving her bald.
 
Pinkie: “AHHH! DERPY! LOOK WHAT YOU JUST DID TO MY HAIR!”
 
Derpy: “Heh, heh, heh… Whoops. Sorry…”
 
Pinkie: “Sorry?! You ruined my hair! I’ll kill you!”
 
Pinkie: Chases Derpy Hooves out of the gym.

@FanOfMostEverything  
No magic, just Pinkie being Pinkie.

Ah. Further proof of magic existing in the human world prior to Sunset’s descent to demonhood. Good to know.

@Background Human  
Just how I like it.

Newbie in MLP?

@BuckET pony  
Swiss Army Hair.

Pinkie Popinski!  

@Bedlam  
Not to mention a mop later in the movie.

@ShimmeringStallion  
Her hair has clearly done much more than that. She has randomly tied cookies in her hair as well, so that’s fun.

So her hair’s a bottle-opener?… Good to know!

How did I not notice this?

Didn’t even notice that and I’ve seen the movie multiple times, what else did I miss?

Pinkie Pie Physics FTW!

Damn, girl, what do you put in your hair?!

Pinkie physics FTW: bottle opener!  
Bottoms up!

I managed to miss this.
 
Thanks, OP.

FiM has many great moments with visual gags like these. Even after seeing an episode for the 10th time, I discover new things in the background.
 
EG was not the pony movie we asked for, but I did enjoy that these visual elements were still there. Props to the animators/story-boarders.

That crate came dangerously close to landing on her elbow…

I didn’t think it was that bad personally, but yeah I love how even human Pinkie is still Pinkie.

Just my opinion: The whole movie was bad, but little funny nods like this one saved it from being an absolute disaster

girl knows how to party

And I thought twisting off a cap on my arm was impressive. (I’m not brave enough to bite a cap off.)

That is fucking talent.