CodreaMicu
2016-09-09T10:52:06Z
dark world monsters don't activate their effects when are discarded by magical stone excavation
(probably the same with "a feather of the phoenix" and "dragged down into the grave")
JoJoToast
2016-09-09T11:01:51Z
Excavation discards as a cost, not an effect, so Dark Worlds discarded by it don't meet their trigger. DW will be triggered by Dragged since that discards as an effect. Feather does it as a cost so it won't trigger DW's.
The Mother Toast wrote:

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hexanort
2016-09-09T11:43:03Z
basically anything that say "Discard X card;" or "Discard X card to" wont trigger dark world since those discards are cost, not effect