Whenever an opponent attacks you, choose target creature attacking you. Put a stun counter on that creature.
: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Lulu is a mono-blue defensive commander who stun-locks attacking creatures to fog incoming damage, then leverages a repeatable proliferate ability to snowball any counters in play. Early game you durdle, set up board control and card advantage, then proliferate engines (planeswalkers, +1/+1 counters, charge counters, or even more stun counters to keep attackers tapped) to grind out the game. You typically win by going wide with proliferated tokens/walkers or by assembling a counter-based combo or alternate wincon while opponents can't profitably attack you.
Free, repeatable defense: every opponent's attack on you tax-locks a creature with a stun counter, making you a poor attack target.
Built-in proliferate is one of the strongest counter-payoff buttons in the format, supporting countless synergies.
Mono-blue gives access to the best counterspells, card draw, and protection in the format.
Excellent at protecting planeswalkers and snowballing superfriends or experience/charge counter strategies.
The defensive ability only triggers when YOU are attacked—it does nothing to protect teammates or stop noncombat damage and combo.
Mono-blue struggles with enchantment/artifact removal and lacks board wipes outside of bounce.
Reactive playstyle can make you the table's slow durdler with a weak proactive clock.
Stun counters only stop one creature per attack declaration and don't prevent trample/evasion math if you fall behind.