This is great! I didn't see that card in my searches because I just wasn't looking. It's an artifact so it has interactions with Scarecrone, it's a two drop, so I can play it early and help with my other creatures, it's an "as you play" trigger so Reaper King will benefit, and it's a creature, which increases my threat density.
All in all, Metallic Mimic seemed like a great idea so I made the decision to cut the Barbed Sextant to make space. That was a hard decision, because extra cards are good but Worldly Counsel has been such a rockstar, I thought the creature density mattered more.
This had times when it worked out, as with my match against Lauriel.
And times when it didn't go as well, as against Fuz.
Because, against really aggressive decks, I need to draw Collective Restraint and I didn't get one, not a single one, against Fuz.
Which means it's time for me to let go of the Glory of Cool Things that is Eerie Interlude. I like this card, I have cast this card and had it be fun! But I need to have a Ghostly Prison effect out by turn 4 and without the extra draws from the Barbed Sextant, I want to ensure that Worldly Counsel gives me a shot.
As for the matchup pictured? Weeeellll...this is why sideboards are made. Destroying most of the lands so my opponent cannot attack is a very good strategy against anything but decks that want to mill me or decks that don't care if they have lands.
These are, admittedly, very narrow strategies and I shouldn't run into them very often. What's more likely is that I would run into countermagic and there isn't a ton I can do about that. Like a great many decks I build, playing around countermagic will take patience and, again, a sideboard to help me resolve spells that I need resolving.
Nonetheless, I feel like I've got this deck in a better place and until there are more scarecrows, I think I've got to let this dog lie.