It was big enough to provide 1,500 servings:
Measuring 12 inches tall and 24 inches wide the cupcake weighed 150.7 pounds and used 15 pounds of fudge filling and 60 pounds of yellow icing.
Makers cakes.com created the cake as part of celebrations for the SpongeBob SquarePants' 10th anniversary at the Minneapolis Mall of America.
An adjudicator from Guinness World Records was on hand to inspect (and sample) the cake before declaring it the world's largest cupcake.
Link via Instapundit