Tony Stark manufactured them and it took him a week. So Cassandra Nova was twiddling her thumbs for a week while the x-men waited for those helmets. Wonderful plotting
Ah, plot induced stupidity: the X-office's best friend
holy balls.
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"Cable was right!"
He's not wrong. The X-men may have been created first but this wasnt a concept that was a part of their mythos for the 60 or so years they've been around since now. Its just like people calling the Inhumans a ripoff of X-men when Terrigenesis became a global phenomenon and they were adopting many of the X-men's concepts a few years ago