Lurking Roper + Cryptolith Rite + Judge of Currents + Arcane Adaptation

Lurking Roper

Cryptolith Rite

Judge of Currents

Arcane Adaptation

How it works

1. Activate Lurking Roper by tapping it, adding one mana of any color.
2. Judge of Currents triggers, causing you to gain 1 life.
3. Lurking Roper triggers, untapping itself.
4. Repeat.

This clever engine turns a humble insect into a self-sustaining mana factory by rewiring the battlefield's biology with Arcane Adaptation naming Merfolk. Once that type-shifting foundation is set, Cryptolith Rite grants Lurking Roper the ability to tap for any color of mana. Tapping the Roper to fulfill Cryptolith Rite's mana cost simultaneously satisfies Judge of Currents, which rewards the newly minted Merfolk's tapping with a burst of life. That lifegain instantly triggers Lurking Roper's untap ability, priming the creature to tap all over again for an endless loop of colored mana and life.