The video uses a common "ruin" to "reveal" format that plays on viewer expectations, creating a satisfying reveal of a desirable outcome (beautiful black hair).
Summary
The creator initially pretends to be ruining her hair by dyeing it at home, but then reveals it's a joke and that she loves the black hair color. She then transitions to showing off her styled black hair.
Structure
1Creator shows hair with dye, claims she's ruining it
2Creator reveals it was a joke
3Creator shows off her styled black hair
On-screen text
watch me RUIN my hair
dying it at home...
jk...you can never go
wrong with black
Transcript
That's why I'm throwing shade like it's sunny... jk... you can never go wrong with black
Original caption
not the color I was expecting but this MIGHT be MY color… #hairtransformation ib: @Dr Ree