Worse thing someone stole from you?

[Moonstar101]

What is the worse thing a dark player has stolen from you, and why? Maybe it wrecked your strategy, maybe it gave the dark player a opportunity to destroy you. Whatever the reason pls tell.

[Linkcat]

Torb stole my firstborn son, that wrecked me pretty hard.

[Monox D. I-Fly]

What is the worse thing a dark player has stolen from you, and why? Maybe it wrecked your strategy, maybe it gave the dark player a opportunity to destroy you. Whatever the reason pls tell.

As a mono-Water player, that would be Shard of Patience.