Can someone help settle an argument?
Once the Sand Sphinx building is flooped does it remain on the board or is it then discarded?
I'm not sure why you (or whoever) would think the Sand Sphinx would be discarded.
The card states:-
FLOOP >>> Return a Creature you
control in this lane to its owner's hand.
The Sand Sphinx isn't a creature, it's a building so it's not eligible. Nothing else seems to suggest that the Sand Sphinx should be discarded.
The use for the Sand Sphinx seems to be a way of effectively healing the creature in this lane. Unless I'm missing something, I don't see why flooping it would require it being discarded.