There are those who draw false comparisons between the tech-magi of the Adeptus Mechanicus and the xenotechnologists of the necron race. There can be no mercy for such heretics.

Cryptek

{1}{B}, {T}: Choose another target artifact creature you control. When that creature dies this turn, return it to the battlefield tapped under your control.

Warhammer 40,000 Commander

All Cryptek's activated ability does when it resolves is set up a delayed triggered ability. If the target artifact creature isn't put into a graveyard this turn, that ability never triggers. If the targeted artifact creature is put into a graveyard this turn, that ability triggers and resolves like any other triggered ability.