"Time" for some card ideas

[Turlututu]

Sand Cat
2
Creature
1|1
Keeps modifiers when rewund. Instead of dying/When it dies, rewinds itself and gains 2|2.
(I'm not sure if it should trigger death effects or if it should bypass them like Fenghuang — both options have their pros and cons)

Lucky Seven
7
Spell
If you have fewer than 7 cards in hand, add Singularities to the top of your hand until you have 7 cards. Then, if the 7th card in your hand is a spell, copy its effect. Otherwise discard your hand.

Time Machine
5
Spell
Send target creature to the previous turn.
(Gamestate is recalculated as though the creature had existed as-is the turn before)

[Hitei]

Wouldn't the Sand cat be broken with pandemic and the death nymph? it would keep getting poison counters and "dying" over and over while keeping the poison counters on it.
Would also love to get many overdrives on itself since "it wouldn't die" but will keep having more and more negative HP..

The Time machine sounds super weird, albeit what it just does is remove summoning sickness and trigger a passive and an attack. way too costly when you have in time the Shard of Readiness that does "most" of what this does with more combos/splash. your card however would work for 1OTK as I suppose creatures like Crimson dragon would have hit for its attack "on the previous turn"

[Turlututu]

Aflatoxined Black Cat becomes a Malignant Cell, I assume Sand Cat would work the same way. Regular poison works, but is better on Black Cat (doesn't block your draws + doesn't gain HP).

You can't stack up overdrives since it's a replacement effect.

Time Machine sounded whackier in my head :-(

[Hitei]

Yeah the black cat turns into a malignant cell, but you need to check what happens if a creature protected by Feng huan (which is the effect most similar to sand cat effect) goes to hand or not, since if it does there's a possible nice deck idea growing on my mind.

I forgot that overdrive is a replacement, duh. thanks for remind me.

And about time machine, don't fret over it. in our imagination cards looks super cool etc... yet we also have to see how it really works mechanically inside the game (too see what's possible or not) plus from experience I can tell that many of my ideas that sounded awesome when I proposed them first time, after a few days many of them looked weak so I tried to improve and think of more.

Would like to see what you come up with for other elements as well. I loved your "sand cat" the most.