Converted Mana Cost

[KulrathKnight]

Let's say I have {Urza's Incubator} out and I choose Wurm. If I use {Worldly Tutor}, would it only cost 5 mana to play {Panglacial Wurm} from my library or would he still cost his full amount?

Similarly, if I have the incubator out, will {Chord of Calling} only require 5 as the X cost to bring out a {Plated Slagwurm} from my deck?

[BlackJester]

Let's say I have {Urza's Incubator} out and I choose Wurm. If I use {Worldly Tutor}, would it only cost 5 mana to play {Panglacial Wurm} from my library or would he still cost his full amount?

Similarly, if I have the incubator out, will {Chord of Calling} only require 5 as the X cost to bring out a {Plated Slagwurm} from my deck?

Good questions. {Urza's Incubator} doesn't change the actual casting cost, only how much you have to pay. So in the first case, you would pay two less since you're casting the Wurm.  In the second case, the chord looks at the actual casting cost for the {Plated Slagwurm}, so 7.

[KulrathKnight]

Ok thank you. I've been wondering this for a while and wasn't sure how it worked. So cards that reduce the cost like the incubator and {Emerald Medallion} reduce the "cost to cast" not the "converted mana cost", right?