Escalate + Dark dwellers

[Skullguy725]

If my {goblin dark-dwellers} targets a spell with escalate in the GY (for example, {collective brutality}), Can I pay the escalate costs while casting it for free?
Thanks

[Skullguy725]

Nevermind rulings says it right there. Ignore this

[Kaylesh]

Just for others wondering the same. "Without paying it's mana cost" is considered an alternative cost. You can only use one alternative method of paying, thus you cannot use other alternative costs, such as surge.
You can pay additional costs, and must do so if it is a mandatory cost ({bone splinters} for example). So kicker, escalate, etc. can be payed in addition to the (free) casting of the spell)