Donde tas is a shortened form of dónde estás, meaning where are you in Spanish, and mmgv is short for mamaguevo, a crude slang insult common in Venezuela and the Dominican Republic. The clip circulates mainly as a WhatsApp style voice reaction rather than from a confirmed film or show. Shared in chats and short edits, it works because the slang spelling is how people actually type the phrase when they are looking for someone who has gone quiet.