This was the Complex Question fallacy, plurium interrogationum in Latin, or omplex-cay interrogationum-way in Bullshit, the language in which it normally used. It is not always considered a logical fallacy since it is based on a false assertion of fact, rather than improper logic. The question presumes you have taken the opposite position of the prior statement when you did not. Just like ‘Have you stopped eating your boogers’?
But he doesn’t just accuse me of having a position opposite his; he REASONS that I do based on the fact that I asked him for evidence. The first part of the exchange is crucial, not just the last sentence.
If I say the moon is made of green cheese, that’s just an incorrect statement. But if I say I know the moon is made of green cheese because all my friends say so, that’s a fallacy, right?
OK.
The “fallacy” of concluding that you believe that regular Sneetches are as intelligent as Star-bellied Sneetches is the Strawman (first suggested by GHO57 far above), which is not a formal logical fallacy but more of a rhetorical device of arguing against a point that your opponent never actually made.
There is no fallacy involved in his argument that Star-bellied Sneetches are 30% more intelligent than regular Sneetches, because he never actually makes an argument for it.
Perhaps I have misunderstood your question. My responses above assume that you want to know the fallacy of making his point by accusing you of taking the opposite point. It now appears that you want to know the fallacy leading to his conclusion that you are taking the opposite position, which has nothing to do with arguing his original point at all.