Sinking Feeling + Hex Parasite + Vizier of Tumbling Sands + Chromatic Orrery

Sinking Feeling

Hex Parasite

Vizier of Tumbling Sands

Chromatic Orrery

How it works

1. Activate Chromatic Orrery's second ability by tapping it, adding 5.
2. Activate Vizier of Tumbling Sands by tapping it, untapping Chromatic Orrery.
3. Activate Vizier of Tumbling Sands by paying 1 and putting a -1/-1 counter on it, untapping it.
4. Activate Hex Parasite by paying 2, removing the -1/-1 counter from Vizier of Tumbling Sands and giving Hex Parasite +1/+0 until end of turn.
5. Repeat.
6. Once you have infinite mana, you may instead use Chromatic Orrery's second ability to draw infinite cards.

This clever engine turns Vizier of Tumbling Sands into a self-untapping mana producer, anchored by Sinking Feeling granting the crucial activated ability to place and pay off -1/-1 counters. Hex Parasite acts as the clean-up crew, feeding on life to efficiently strip away those pesky -1/-1 counters so the Vizier can keep on untapping without perishing. Meanwhile, Chromatic Orrery provides the massive mana output needed to fuel the loop while also letting you spend that mana as any color, eventually converting your infinite untaps into an infinite card draw engine.