Pen Pen
Pen Pen (Sometimes Pen-Pen or Pen^2) is Misato's pet, a warm-water penguin, who lives in her freezer. She apparently took him with her when she left her previous job.
One popular (although usually not entirely serious) theory among fans is that Pen Pen was in fact the mastermind behind SEELE, NERV and Gehirn, orchestrating all the major events in the series from the Second Impact in 2001 up to the Third Impact in End of Evangelion. The proverbial "Penguin behind the curtain" that we are not to pay attention to.