Wall of Slime

Creature - Ooze Wall

Defender

: Until end of turn, Wall of Slime may attack as though it doesn't have defender. When it deals combat damage to an opponent, you may instead destroy target artifact or enchantment they control.

2/5

Now THAT'S some old school magic!

Make a brand new Planeswalker using some type of magic we haven't seen before. There's a lot of them out there so good luck lol

Nutama, Pride of the Savannah

Legendary Creature - Cat

Vigilance

Landfall - Whenever a land enters under your control, gain 2 life and create a 1/1 white Cat creature token.

Whenever a Plains enters under your control, you may have Nutama fight target creature you don't control.

6/6

Make a Whale with Dredge or another graveyard mechanic

Emanator of Flames

Creature - Elemental Giant

When you cast Emanator of Flames, as it enters the battlefield, it deals damage equal to the number of mountains in play divided as you choose among any number of targets.

5/6

Basically the cycle would be the same idea but for each of the basic land types.

What makes them mythic is that the trigger happens AS they enter, not WHEN they enter.

It triggers on the stack as it resolves. This is a significantly tighter restriction and timing event.

Feel free to make another Emanator of XXXX, but the cycle is pretty self-explanatory.

Scry, gain life, make tokens +1/+1 counters, -1/-1 counters, lose life, etc etc etc

So, wild instead

Sphinx of Perplexing Temptations

Creature - Sphinx

Flying

Whenever one or more creatures attack you each turn, the next spell that player casts on their turn costs X less, where X is the number of creatures they attacked you with.

At the beginning of each players end step, if that player didn't attack you, they draw two cards.

4/4

I'm not sure what kind of a deck would want to run this as it incentives your opponent both to attack you as well as not to attack you.

But fun fact, since you can't attack yourself you'll always draw two cards during your own end step.

Make a card that would make this creature useful in an Esper Commander deck