Goblin Welder vs Spellskite

[Kap'n Cook]

I have goblin welder in play and my opponent has a spellskite

Let's say I activate Welder targeting my great furnace in play and my grindstone in the yard. Does spellskite screw up the exchange?

[phazonmutant]

First, let's get the Oracle on Welder and Spellskite.

Goblin Welder
Creature — Goblin Artificer 1/1, R (1)
{T}: Choose target artifact a player controls and target artifact card in that player's graveyard. If both targets are still legal as this ability resolves, that player simultaneously sacrifices the artifact and returns the artifact card to the battlefield.

Spellskite
Artifact Creature — Horror 0/4, 2 (2)
{UP}: Change a target of target spell or ability to Spellskite. ({UP} can be paid with either {U} or 2 life.)

That's not quite clear, so let's look at the FAQ for Spellskite.
One of the items:

If changing one target of a spell or ability to Spellskite would make other targets of that spell or ability illegal, the targets remain unchanged.

Changing the "target artifact a player controls" to Spellskite would make the graveyard target illegal because Welder specifies they must be the same player. Therefore, Spellskite's ability doesn't do anything.

[cdr]

Great answer.