Boule de Combat Samouraï Supralourd CROS-FR008

If all the monsters you control are "Superheavy Samurai" monsters and you have no Spell/Trap Cards in your Graveyard, you can target 1 face-up monster your opponent controls that has a Level, send it and this card from the field to the Graveyard, then Special Summon 1 "Superheavy Samurai" Synchro Monster from your Extra Deck whose Level is equal to the combined original Levels of those 2 monsters in the Graveyard. (This Special Summon is treated as a Synchro Summon.) You can only use this effect of "Superheavy Samurai Wrecking Ball" once per turn.