Saheeli, the Sun's Brilliance + Mana Echoes + Signpost Scarecrow + Pestermite

Saheeli, the Sun's Brilliance

Mana Echoes

Signpost Scarecrow

Pestermite

How it works

1. Activate Saheeli by paying and tapping it, creating a token copy of Pestermite with haste.
2. When the token Pestermite enters the battlefield, it and Mana Echoes trigger.
3. Resolve the Pestermite trigger, untapping Saheeli.
4. Holding priority, if you control less than four creatures that share a creature type with Pestermite, repeat steps 1 through 3 one additional time.
5. Resolve all Mana Echoes triggers, adding C for each creature you control that shares a creature type with Pestermite for each trigger resolved this way.
6. Activate Signpost Scarecrow twice by paying 4, adding .
7. Repeat.