The joke was that "Brazillion" sounds like all the weird words English speakers invent to describe huge incomprehensible numbers, like they usually say "bazillion", "bajillion" or whatever. And anacondas are most common in Brazil so that's the other half. And no, it wasn't me who submitted this joke.
Savjz, a "bazillion" is English slang (or gibberish if you will) that means "a lot." For instance, how much debt does the US have? A bazillion dollars lol. And since the Amazon is in Brazil, an obviously amazing pun is formed when asking how many men it takes to catch an anaconda.
