Looks like Nintendo has a bug in the very addictive Animal Crossing: Wild World and is working hard to fix the problem:

"Nintendo would like to thank its numerous Animal Crossing: Wild World fans for helping identify and correct an unforeseen issue with the game. Some users of the community-simulation game for Nintendo DS noticed that receiving a letter containing a ‘Red Tulip’ could cause interference with gameplay," Nintendo said in an official statement issued to the press.

"We have isolated the problem and determined that there was a temporary error with the upload tool when this letter was posted. Thankfully we have been able to limit the number of people affected by removing the related file from circulation. Players who have received the letter should delete it before placing the Red Tulip anywhere in their characters’ homes."

The statement goes on to emphasise that "tulips themselves are not the problem", noting that other colours do not cause any disruptions to gameplay. In addition, the Red Tulip only results in problems if players plant it indoors.

Nintendo pledged to find a solution to the problem, stating: "We are investigating ways to remove the item from the homes of players who have experienced gameplay interference, and we will update the Animal Crossing: Wild World FAQ on NintendoWiFi.com when we have more information to share."

From Gamesindustry.biz.