Color Identity: U

Initial Card State
- All permanents on the battlefield.
Notable Prerequisites
- Grim Monolith does not have summoning sickness.
Steps
- Activate Grim Monolith's first ability by tapping it, adding ({C} magic symbol)
({C} magic symbol)
({C} magic symbol)
. - Activate Karn by paying ({1} magic symbol)
, causing Grim Monolith to become an artifact creature until end of turn. - Activate Grim Monolith's last ability by paying ({2} magic symbol)
, untapping it. - Repeat step 1 and 3.
Results
- Infinite colorless mana.
Bracket Tag
This combo has been estimated to be Powerful (Bracket 3+).