I was just fishing around the WotC website and look what I found.

Mold Demon:
  Note - Also see Comes Into Play Abilities, Rule E.3.
  You must sacrifice two Swamps whenever the creature is brought into play.
    This includes Clone, Vesuvan Doppelganger, Animate Dead, or
    Resurrection.  In all these cases Swamps need to be sacrificed.
    [bethmo 06/25/94]
  A creature leaving Oubliette or Tawnos's Coffin or phasing in does
    not cause "comes into play" effects to happen again so it will not
    require a sacrifice in those cases. [Aahz 07/05/95]
  A Vesuvan Doppelganger switching forms to a Mold Demon will not
    require a sacrifice. [Aahz 07/05/95]
  The sacrifice is done as a triggered ability just after it enters play.  It
    is not paid on announcement. [D'Angelo 10/27/95]

I especially found the part where it says that, "a creature leaving <...> and
phasing in does not cause "comes into play" effects to happen ..." intriguing.

This means that the spike worker / phasing , treasure hunter / phasing,
<tons of sh*t> / phasing, will not allow you to perform the effect of its
coming into play.

Comments?

Froccer