MTG Combo: Dreamstone Hedron + Dross Scorpion + Pentavus

This combo generates infinite mana, infinite token creatures being created, infinite +1/+1 counters being added/removed, and infinite token creatures being sacrificed.

Combo is relatively easy to understand, tap the Dreamstone Hedron for mana, and activate Pentavus' remove a +1/+1 counter to create a token ability, and then sacrificing that token to put the +1/+1 counter back on Pentavus. This nets you 1 colourless mana. The sacrificing of the artifact creature token triggers Dross Scorpion, targeting Dreamstone Hedron, untapping it and letting you repeat this process.