LogFAQs > #974672036

Why would it blow up the opponents copies? They werent played. Negasonic blows up the next card played, not next card added. By now you should know what qualifies as a played card and what doesnt. Only a card placed manually by the player from hand to location is considered played (with the sole exception of Mysterios illusions, which also count as played, because otherwise it would be obvious which was real in many circumstances)

All 4 Negasonic blowing up is also exactly what I would expect. The next card played is the next card played, regardless of how many Negasonics are present.