fakestreet
you seem to have a misconception about the card.

they just need to have a creature, ANY creature, or an artifact for this to swap with Grid Monitor.
That's what I was trying to tell him.
sweatdrop Confusion in the Ranks does NOT look at the
subtype (ie. Creature -
Beast, or Artifcat -
Equipment) it looks at the supertype (ie. Creature, Enchantment, Artifact, nothing further). Therefore, if your opponent has ANY creature or ANY artifact in play when you play Grid Monitor, you can make the swap.
Fakestreet, are you sure Confusion triggers on itself when you play it? From what I've experienced with the card, any copies you play AFTER the first is swapped, but the first one can't trigger itself because it's not yet in play for it's ability to activate...
EDIT: Checked on the rulings. Nevermind Fakestreet, you're right. It does trigger itself when it comes into play. In addition, if you play an Artifact Land you can swap it for a Land, as it is an Artifact when it comes into play, and Land is another supertype. This gives me a whole new outlook on the usefulness of the card (land grabbing).