Player A summons Debris Dragon and activates it's eff to summon Lonefire Blossom and tries to activate its eff to tribute itself and summon Dandylion.

Now, I'm looking at it this way: not so long ago, when Rescue Cat wasn't banned I tried to use the same strategy as mentioned above, but instead of Lonefire I used the Cat. A friend of mine told me I couldn't because it's an effect. And he was partially right because it isn't allowed in TCG because it is a cost only in OCG. That's where it gets tricky for me: is it the same with lonefire?

I have also checked the Wiki, and in there was a ruling proving I was right, however, I do not trust the Wiki because someone could've editted it. So guys, am I wrong?

Oh, and here's the link:

http://yugioh.wikia.com/wiki/Card_Rulings:Lonefire_Blossom

Answer to this question is very simple.

Debris Dragon negates effects that activate on the field. No matter where Lonefire will be in the time of resolving, the effect of Lonefire activates on field and thus, will be negated by Debris even if it's tributed as a cost.

You can ask how it is possible then with Skill Drain if it negates as Debris but, Skill Drain negates effects if the Monster that started the effect is still face-up on the Field which is why you can use Lonefire to tribute itself if Skill Drain is active.

Confirming Amy.

Skill Drain only negates effects where the monsters is face-up on the field when it resolves, whereas Debris Dragon negates it as long as it's activated while on the field, regardless of where it ends up.

Thanks guys. Wait a minute, so does that mean I could've used it with Rescue Cat when I was in a tourney? If yes, I'll be angry for believing my opponent. Anyway, you can close the topic now.

No you couldn't.

Got it, nevermind. So if it doesn't say "tribute", does it mean it's not a cost?

That's not why Cat doesn't work with Debris (to begin with, you can't even revive Rescue Cat with Debris Dragon as Cat is level 4). The reason it doesn't work is because Rescue Cat's effect activates on the field so it will be negated. Dandylion works with Debris because the effect activates in the graveyard.

No more confusion on my side. Thanks. Oh yeah, you actually can summon rescue cat with debris. I bet you've misread it but it's ok.

When this card is Normal Summoned, you can Special Summon 1 monster with 500 or less ATK from your Graveyard in Attack Position. That monster's effect(s) is negated. This card cannot be used as a Synchro Material Monster, except for the Synchro Summon of a Dragon-Type Synchro Monster. The other Synchro Material Monster(s) cannot be Level 4.

That's the effect of Debris.

True. I mixed up the "The other Synchro Material Monsters(s) cannot be Level 4" part with not being able to revive a level 4 monster.

Which comes to conclusion that you never want to summon Cat with Debris since you cannot use Cat's eff nor use it with Debris for Synchro summon