Endoxosphinx

Well, that was fun.


Endoxosphinx
Cannot be Normal Summoned or Set. Must be Special Summoned (from your
hand or Graveyard) by discarding 1 Rock-Type monster except
"Exdoxosphinx", and cannot be Special Summoned by other ways. Once per
turn: You can change this card to face-down Defense Position. If this
card is flipped face-up: You can Special Summon 1 Rock-Type "sphinx"
monster (from your Deck) in face-down Defense Position. If this card
leaves the field: You can add 1 "Exxod, Master of The Guard" from your Deck to your hand.

Aside from the fact Exxod's 0 ATK makes him searchable by a few things, having a card that not only searches it but can also fuel its Summon is quite nice.
Though, personally, I think you should have its cost Banish the monster instead of discarding. I dunno', just an idea.