Board Thread:Supergirl discussions/@comment-9346948-20161129012248/@comment-27700324-20170102051239

Kaestal wrote: That depends, the Kryptonians apparently invented an "Anti-Every Life-Form except us" bomb, and then Kara says the Dominators have visited Krypton before....

Seems like a handy tool to have when faced with creepy CGAliens That is a likely theory.