When this card destroys an opponent's monster by battle and sends it to the Graveyard: You can place 1 counter on this card. You can send this card with 2 or more counters to the Graveyard; Special Summon 1 EARTH monster from your Deck. If this card would be destroyed by battle or card effect, you can remove 1 counter from this card instead.
I couldn't Special Summon the 2nd Buster Blader in my Deck with BOXer' effect, but I had no problems doing so in the previous duel. The only reason I can think of is because I had my other Buster Blader in my Hand this time... Perhaps the code gives a red light if you have Buster Blader in your Hand, because you can't Special Summon from the Hand with BOXer, and then it just stops looking.
Never mind, apparently I took one of my Buster Bladers out of my Deck after the last Duel, so all is fine.
Today my BOXer with three counters on it has been destroyed by an Ancient Gear Knight with his effect activated. The AGK description says "If this card attacks, your opponent cannot activate Spell/Trap Cards until the end of the Damage Step." So why has it been able to destroy my BOXer?