I really like Historic Horizons embracing the fact mtg is digital and I see it as yet another opportunity for silver border to shine, because silver border is really the only place mtg has embraced that it’s a physical paper game. Dexterity cards (not just Slaying Mantis or Boomstaker type things, but also Hot Fix and Cramped Bunker) , sub games, and caring about people outside the game, and even speaking (Gotcha wasn’t great, but there’s other ways to play with that). Here’s hoping I’ve given you another talking point in your quest to green light another un-set! :)

You’re preaching to the choir, but I appreciate the enthusiasm for Un-sets. Feel free to communicate with others Wizards folk that you’d like to see more Un-sets.

Unruling question- if my opponent double majors a slaying mantis, are they allowed to pick what they throw at the table for the token, or does it have to be a magic card (or magic card sized object)?

It has to be a Magic card (although Magic-card sized tokens from boosters are fine).

Un rules question: If the 2/2 homunculus token from handy dandy clone machine somehow becomes a copy of slaying mantis as it enters, how do I throw my hand from three feet away? Can I punch a creature to fight it?

There’s no way to throw your hand three feet, so it can’t do the enter the battlefield effect.

FYI the world's BEST game of Magic has been played by my wife and I and no other can hope to top it: An Enter the Dungeon subgame under the table. Old Fogey played. Frankie Peanuts used his question and Sword of d&d to make a dragon. BINGO was achieved. A 10/10 BINGO was successfully blocked to survive with 1 life. Slaying Mantis was thrown. Frankie Peanuts - "will you give me sweet sweet kisses until end of turn?" meant the final turn included much kissing. And this was all under the table. 

I congratulate you on playing the best ever game of Magic. Thanks for sharing.

Where is physical dexterity on the Gotcha! scale? Such as Charm School and Slaying Mantis.

Physical dexterity is a 2. We do limited amounts, but we always do a little.

Un-question, how do you handle Slaying Mantis token copies? In particular if you represent them with a dice? Do you just throw the original?

I use the original card for the tossing.

Hey Mark, is there any way a player can enter the battlefield in place of a creature? I'd like one of my friends to be able to body slam the table in the stead of my Slaying Mantis doing so.

I’ll see what I can do with the floor rules.

does slaying mantis affect creatures outside your game? i.e. if you're playing at a draft with other games going on around you, can those players still touch cards?

Unless an Un-card specifies it affects other games, it, by default, can only affect your game.

My hand is being used to represent a Handy Dandy Cloning Machine token. What parts count for cards like Slaying Mantis? The full hand, or just the part around the two fingers? What about the other fingers?

The full hand.

For Slaying Mantis, should you throw it from 3 feet away horizontally, or could you throw it at a diagonal, as long as it's at least three feet away in any direction?

3 feet away horizontally. It should not be thrown vertically.