I am a bit nervous about whether this can be used to just take all the turns. I mean, it fits the flavour, but the gameplay would be bad if it's too easy.

You'd need 10 mana to do that, first time round. Say 8 lands and a Professional Welder. You pay 10 to cast and activate it, and it goes third from the top. On the extra turn, you activate Decorated Detector in your upkeep, putting 2 on the bottom and drawing TT, gaining a Treasure. Recast it (you've spent a total of 12 including the Treasure) and... hm, you're just spinning your wheels at that point. You also need another Welder or some evasive creature to actually win. Or just 2 more mana so your Welder can be pinging.

If you use Pursue Perfection instead of the Detector, you still need 12 mana and don't get a Treasure to help you, but you're drawing an extra card per turn, so you can be playing lands, and eventually you'll be able to find a win condition. Hah: PostCrush are able to use the Time Twirler to Pursue Perfection, but unlike in the film, here it actually works :)

I think a combo piece that means you need 12 mana and a few cards to go infinite isn't a problem.

How much does "Untap all permanents you control and draw a card" cost? 5 and 5 and sorta-exile-this-card is probably fine.

If you activate it during a single opponent's upkeep it basically allows you to take three turns in a row. Intended?

This also means once you reach the mana threshold to activate this you only need a consistent way to pay five mana per turn to keep the infinite turns going.

Are you only concerned with combinations within the set?

Oooh, I hadn't even realised the "End the turn" could end an opponents turn. Yeah, ok, that's kinda scary.

Yeah, that's why the only card that can repeatedly do that, Sundial of the Infinite, has that restriction

I'm primarily only concerned with interactions within the set - or at least, within the wider scope of the 7600 cards designed for the Friendship Is Card Games blog. I'm planning a series of perhaps 4 sets compiled from those cards, intended for limited play individually and constructed play with each other.

I guess FanOfMostEverything was pushing the envelope here. I assume his intent is indeed to allow taking 3 turns in a row, if you pay 10 mana on the "first" of those.

Is it true that it only needs five mana per turn to keep infinite turns going? I can't see how that works.

I activate this, begin my extra turn, and untap. TT is 3rd from the top. I draw and it's now 2nd from top. I draw or scry past an extra card somehow with my 5 spare mana. Then I take my regular turn, and draw and cast TT. But then it's your go and I've spent my 5 mana for this cycle. After your go, yes, I untap, draw a new card, and wait for your upkeep, then pop this again.

If I'm completely without scry or help, then I think this changes a cycle of "3 of my turns - 3 of your turns" into a cycle of "4 of my turns - 2 of your turns". Which is equivalent to a max level Lighthouse Chronologist, at the cost of paying 5 mana on two of my four turns rather than 9 mana up front.

Once I do get some source of scry or extra draw (which a deck built around this would certainly include) then yeah, it gets a bunch more scary.

Mitigating factors? Well, the set does have quite a few disenchant effects... and not many counterspells...

It certainly may well be that this design is fundamentally flawed. Most of Fan's best designs are uncommons; pushed mythics are hard for any of us to design right.

> I draw or scry past an extra card somehow with my 5 spare mana.

Doesn't cost mana to activate Sigiled Starfish and Merfolk Looter; one copy of each means you have The Time Twirler back in hand the turn after you activated it.

And that's just counting cases when you haven't a second copy already and space them out so you can cycle through the two of them in your top of library.

Though I'm just basing this on stuff that is commonly available. You can obviously decide to specifically avoid this kind of ability in your environment.

It's really hard to say whether the deck comes together reliably without testing. But this card IMO puts restraints on fast mana for blue and free looting.

It is not a bad thing for a format to have a combo that defines the speed and this totally has the weakness that it takes two turns to set up if you want to get it going before you have ten mana (or equivalent), so the card might just be okay to have around and kept in check by faster aggressive decks.

I just doubt that a deck that actually plays this will usually allow the opponent to get another turn after even a single activation of this - if Nexus of Fate can accomplish problematic status by shuffling itself into a random position of the deck, then this can do so by putting itself into a predetermined position of the deck.

Note: One thing I have underestimated so far for this card is that the opponent gets to untap during each cycle, so instant speed solutions are still an option to interrupt the combo.

They only get to untap if you want to let them - you can just activate it in your main2 if you want to keep it up forever.

But then you only get one extra turn until their next turn (since you don't prematurely end their regular turn) and need more resources to keep the combination going. Once you reach ten mana, you would certainly opt for that.