Triangle eyes, triangle nose -- the jack-o'-lantern was missing something.

Stevan Guimaraes leaned away from the table and cocked his head to one side before sawing away near the bottom of the pumpkin. After a few minutes, Guimaraes smiled -- the pumpkin smiled back.

This was the first time that 18-year-old Guimaraes carved a pumpkin. They don't carve pumpkins in Brazil, where he's from, but he had seen them in Halloween movies. A student in the Rotary Youth Exchange program, Guimaraes lived in two other cities before finishing his year in the U.S. at Kelly Walsh High School.

Guimaraes told his host dad that he wanted to carve 20 pumpkins. That was before he found out that the insides have to be removed before carving.

"Now I know that one is enough," Guimaraes said. "It's fun to carve, but not to take the stuff out."

Cleaning the guts out of the pumpkins was a common complaint among Natrona County's exchange students who carved pumpkins -- most for the first time -- at a Halloween party on Thursday night. Their countries don't celebrate Halloween, a strange American tradition. Wear funny clothes? The inside of the pumpkin isn't saved and cooked? People give away free candy?

"I don't really understand it," Cristina Jimenez Sanchez, a Natrona County High school student from Spain, said. She wore a bat headband and carved a monster into the giant pumpkin she had cleaned out the night before. Throwing away the pumpkin's insides surprised Jiminez, said host mom Velda Sivertson.

"As Americans, we're a very wasteful society," Sivertson said.

For every scary-faced pumpkin, there was one proudly decorated with "KW" or "NC." Host families shared the holiday with their exchange students with parties, more pumpkin carving and trick-or-treating.

Guimaraes planned to dress up as a pirate today and couldn't wait to trick or treat, although he knows he's probably too old.

"I just want to be a kid," he said. "It's American."

They were less thrilled about the Halloween game of bobbing for apples. While younger kids stuck their faces in a tub of water, the high school students -- American and from abroad -- took pictures and danced silly to "Monster Mash." Their glowing jack-o'-lanterns watched from the side.

Reach education reporter Jackie Borchardt at (307) 266-0593 or at jackie.borchardt@trib.com. Read her education blog at tribtown.trib.com/reportcard