An MIT sophomore was injured yesterday afternoon when a pyrotechnic device, intended for use as a theater special effect, exploded in his hands before a crowded classroom.

The student, whose name was not released by Institute officials, was rushed to Massachusetts General Hospital.

The incident was part of a prank intended to promote a biannual Halloween party sponsored by the Phi Kappa Sigma fraternity, according to an MIT spokesperson.

Just after noon, a group of students, cloaked in Halloween costumes, entered an MIT lecture hall in a building known as Lobby 10.

The student who was injured intended to put the sparkling and smoking device in his backpack.

The plan was to promote attendance at the event--a party known as Skuffle that raises money for the Leukemia Society of America.

But the device exploded in the student's hands before he placed it in his backpack.

"He thought the device would add to the aura by going off in a puff of smoke," said Robert J. Sales, associate director of the MIT News Office.