"I wrecked your metal guy, boss. But look! I made you an ashtray."

Goblin Welder

{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.

*Brash_Taunter:* that ride is a BEAST!
*Thrun_TheLastTroll:* looks like an old ashtray tbh

Secret Lair Drop

Commander Anthology Volume II

Duel Decks: Elves vs. Inventors

Commander 2014

Judge Gift Cards 2011

As the new wording makes clear, both targets must still be legal as the ability resolves in order for it to do anything. If either one or both has become illegal, nothing gets sacrificed and nothing gets returned to the battlefield.