Intruder Alarm + Maskwood Nexus + Katsumasa, the Animator

Intruder Alarm

Maskwood Nexus

Katsumasa, the Animator

How it works

1. Activate Katsumasa by paying 2, causing Maskwood Nexus to become an artifact creature until end of turn.
2. Activate any number of mana-producing creatures you control by tapping them, adding at least 3.
3. Activate Maskwood Nexus by paying 3 and tapping it, creating a 2/2 Shapeshifter creature token.
4. When the Shapeshifter enters the battlefield, Intruder Alarm triggers, untapping all creatures.
5. Repeat from step 2.
6. If creatures you control can tap to produce at least 4, this combo nets infinite mana.

This clever loop transforms Maskwood Nexus into an active factory by leaning on Katsumasa, the Animator to turn it into an artifact creature. Once animated, every new Shapeshifter token you create triggers Intruder Alarm, which untaps all your creatures—including the Nexus and your mana-producers. Because Maskwood Nexus grants every creature type to your spells and permanents, every token enters as a creature to keep the untap chain going while churning out infinite creature tokens, infinite entry triggers, and infinite mana.