Urborg, Tomb of Yawgmoth, Kormus Bell, and Make Obsolete

Prerequisites

• Urborg, Tomb of Yawgmoth on the battlefield
• Kormus Bell on the battlefield
• Make Obsolete in hand
• to cast it

Steps

1. With Urborg on the battlefield, all lands are swamps
2. With Kormus Bell on the battlefield, all Swamps are 1/1 creatures
3. Cast Make Obsolete, giving all creatures your opponent control -1/-1 until end of turn, destroying all their lands

Results

• Destroy all lands opponents control
• Destroy all x/1 creatures your opponents control