Kristen Hanby "pranked" his girlfriend, Jasmine Woodward, by pouring a bunch of blue fabric dye in her bath ... which, of course, left her looking like Smurfette.

After sharing the video of himself cracking up while pulling off the bathtub prank with his millions of followers, Hanby sparked outrage as many felt it was just plain stupid at best ... or totally humiliating to Jasmine, at worst.

Many pointed out the harmful effects the dye could have on Jasmine -- both physically and mentally -- and called it "low-key abuse" instead of a good-humored prank.

Others pointed out even if the prank was fake or Jasmine was in on it -- as she's been for several other Hanby vids -- pranks like this normalize hurtful behavior that clearly oversteps personal boundaries.

So, what do you think?