Magosi, the Waterveil + Nesting Grounds + Karn's Bastion

Magosi, the Waterveil

Nesting Grounds

Karn's Bastion

How it works

1. Activate Karn's Bastion's last ability by paying 4 and tapping it, putting an eon counter on Magosi.
2. Activate Nesting Grounds's last ability by paying 1 and tapping it, moving an eon counter from Magosi to Nesting Grounds.
3. Activate Magosi's last ability by tapping it, removing an eon counter from it, and returning it to your hand, taking an extra turn after this one.
4. Play Magosi from your hand.
5. Move to your next turn.
6. Activate Karn's Bastion's last ability by paying 4 and tapping it, putting an eon counter on Nesting Grounds.
7. Activate Nesting Grounds's last ability by paying 1 and tapping it, moving an eon counter from Nesting Grounds to Magosi.
8. Repeat from step 3.