User blog comment:Stevethebarbarian/Question/@comment-26383550-20151211015831

I can answer both! Mothra is considered weak because people see a giant butterfly and go "weak" and don't really pay attention. (I of course don't.) When we think of a butterfly we think of girls. When we think of girls we think weak. (not true WHATSOEVER!) SO, because of that, we see Mothra as weak. And why Bagan? Because he was the final boss of a video game, the developers wanted it to feel rewarding when you beat the game and so they made a hard boss. Because of  Bagan difficulty, people think that he is super strong. (no pun intended)