It deals damage equal to its power to target creature or planeswalker an opponent controls
The other modes and combinations are also effective, and all of that at instant speed too
Skullclamp Skullclamp might not be the obvious choice for the #2 slot here, but after considering it, I doubt Ill get a lot of pushback
Baba Lysaga, Night Witch and Glissa, the Traitor come to mind, the key being getting that second land without actually spending the mana to sacrifice the artifact
1 Admiral Brass, Unsinkable She Won't Go Down With Her Ship The second coming of Beckett Brass headlined an entire Pirates-themed Commander deck, putting The Lost Caverns of Ixalan's new finality counters on display
The Gearhulk is just great with powerful expensive instants and Mystic Confluence is one of the most expensive and powerful instants you play without the Gearhulk synergy