Random Generator gave me Shrapnel Blast and Assassinate. This is very far from that, I know. But "As additional cost, sacrifice an artifact. Destroy target tapped creature" seemed a bit too random, for what could be a very flavorful experience. So I tried to translate the experience instead, giving your opponent a blade that was cursed to kill its owner when it was sacrificed.

This card was almost:

­
Instant
As an additional cost to cast ~, sacrifice a creature or an artifact.
If you sacrificed an artifact, destroy target creature.
If you sacrifice a creature, destroy target artifact.

...but decided against it. I like that spell... I make add that to a file some day.

Your proposed instant reminds me of Frantic Cleansing.

This is a fun card. I think it's fine for mashups to wander this far from their source material from time to time, but it does make me wonder why in some of your other mashups you feel so constrained to stick to some specific original piece of both cards where putting the two together seems rather odd.

One of the things that constrains me is that I want to 'see' both base cards in my end design. In this card, I can still see the influence of Assassinate and Shrapnel Blast, even if it is from a flavor perspective, instead of a mechanical one.

Though, I must admit, I think some of my defenses have been coming down. After having mashed up some 165 cards, I've gotta stick and move to keep this project interesting to myself. I still want to make the cards noticeable as mashups; it is, for me, what 'sells' this set. But, as I pick up tricks, my definition of 'what is noticeable as a mashup' is changing.

Equipment slot. Although, it does a better job defining the Inefficient creature destruction slot.