It’s basically an offensive joke in Spanish mocking African languages. The viral video translates to “How do you say diarrhea in African?” “Abunda la caca! (Poop abounds, African gibberish)”. Like how some racists might say “Ooga Booga” when mocking African languages. There’s a similar joke where it says “How do you say shooting in Arabic?” “Allí va la bala! (There goes the bullet)” It’s mocking the language yet again.
Person 1 (Laughing): Como se dice diarrea en Africano?
Person 2: …Pues cómo?
Person 1 (laughing, mockingly): ABUNDA LA CACA!