True, digested blood looks black, but usually isnt with thar tar constitution. Also, did you puke enough as the dude in the webm? Im curious, I havent yet see enough examples.
The thing is, if blood touches stomach acid it goes black, thats why esophagus ulcers usually manifedt with red blood puking. Stomach ulcers tend to be black, but not that viscous amd theres this shit when shit-thats-not-shit-yet-but-is-technically-shit goes the wrong way and you poop through your mouth, kinda.