Summary The final four semifinal spots were on the line Tuesday night on Americas Got Talent. The last 12 quarterfinalists had their chance before the judges, and host Nick Cannon told us that for the first time one act would be so huge and so dangerous that it had to be taken outside.

After the judges were introduced, Nick called for the first act of the night...

Da Maniacs: A group of friends who just decided to start dancing together, Da Maniacs said they were taking their craft much more seriously now. The oversized dancers were ready to shake the ground. They started their routine with an homage to The Blues Brothers. It continued with a tribute to the stylings of MC Hammer, which earned them a buzz from Piers. The party-pooper, as Nick called him, explained that he buzzed them because there is a reason that most dancers are not your size. He said there was already a TV competition for them -- The Biggest Loser. Sharon said their melding of dance and comedy was entertaining and she enjoyed it. Howie said that to stand out, you have to be either really good or really bad, and they were somewhere in the middle.

Nu Covenant: The gospel quartet had Howie worried that they werent broad enough to appeal to a Vegas-type audience, and they found during rehearsals that the competition was proving to be more difficult than they had anticipated. They tried their hand at One Republics Apologize. Piers buzzed them at the first attempt to harmonize. Sharon followed with a buzz of her own when they hit the second chorus. Sharon said they looked good, but the harmonies werent working. Howie understood that the weight of live television on their shoulders was clear and they didnt rise to the occasion. Piers agreed, saying they were flat as a pancake for most of it. He said pop songs were not their thing and that they should have stuck with the gospel, which was where they were more comfortable.

Anna & Patryk: The kid ballroom dancers who have been dancing together for four years said theyd been getting a lot of attention from other kids at school. They vowed to get a little less serious and to show America just how much we love to dance. Howie said there was no denying their spectacular talent, but his question is whether what they did was worth a $1 million prize and a headlining Vegas act, and he wasnt sure. Piers sought to be more talent, saying, I do know world-class talent when I see, and adding that he could see them in Vegas. Sharon praised their versatility, having seen them now do three different forms. She said they could do unbelievable business in Vegas.

Lindsey Stirling: The hip-hop violinist from Provo, Utah, said people are often surprised that shes Mormon and a hip-hop violinist. Thats surprising, because every hip-hop violinist Im aware of is Mormon. After having heard about enough -- three-quarters of the way through -- Piers buzzed her. Piers explained that the violin was the problem, saying that she missed loads of notes as she tried to play while dancing around. He said that, at times, it sounded like rats being strangled. Sharon reminded Lindsey how much the judges loved her in the audition, but after having seen her three times, she realized Lindsey needs to be in a group because what shes doing now isnt enough to fill a Vegas theater. Howie hated to say Piers was right in saying Lindsey was great, but all the movement made her not as great.

Doogie Horner: The seemingly misunderstood comedian who was booed off by the audition audience but made it to the quarterfinals, no less. Howie expected it would be tough for Doogie. He survived with no buzzes, and the crowd seemed to enjoy his deadpan comedy, which came with some Hollywood razzle-dazzle in the form of fireworks and background dancers. Sharon said Doogie made Piers laugh. She said hes silly, but she likes him. Howie said its the hardest contest for comedians, and Doogie did great. Piers called it a very uncomfortable moment and reminded Doogie that he once considered him the least funny comedian hed ever seen. But, Piers admitted, it finally got to me tonight, and he had to say the word he never thought hed say: Doogie, youre funny.

Rudi Macaggi: The balancing acrobat said performing is all I have. He said he was a third-generation circus acrobat and performing was his passion. He was going to attempt an act he called the circular saw of death. He did a handstand on a stack of blocks, under which a circular saw was spinning. Midway through the handstand, he pushed the blocks aside and landed on a platform with his head inches from the saw. Piers called it the most extraordinary, dangerous, exciting thing I think Ive ever seen on this show. He said that as he waited for Rudis fall, he wondered what would happen to his own career if Rudi had cut his head off. Sharon said Rudi came from a dying breed and he delivered.

Taylor Matthews: The singer-guitarist said he was living a musical life inspired by his father, who gave up his own musical career for a family life. Piers said in the intro he wanted to see Taylor come out of his comfort zone a bit. After his performance, Piers asked Taylor to critique himself. Piers then said there were a few shaky bits, but there were moments when I saw a real, potential pop star. Sharon said that each time she sees him, his performance gets stronger. She said she couldnt wait to see him again. Howie said this performance was his rockiest, so far, but still predicted hed make it to the finals.

Mary Ellen: Nick called her the sexiest contestant of the night. It was Mary Ellen, who came equipped with backup dancers. She had trouble getting the beat early on, and Piers buzzed her. The boos started pouring in as the performance didnt get any better, but Sharon and Howie left her buzzer-less the rest of the way. Nick had to walk on stage and pull the plug on Mary. Howie, dressed in a Mary Ellen-like wig, called her a trend-setter, and said people would be talking about her Wednesday. Sharon said Mary Ellen didnt seem quite right, and Mary said she had some kind of virus. Piers said the only reason Mary was still in the competition was because of Howies undying love for her.

ArcAttack: The electrifying group that said they make music with electricity. Nick said they were asked to take their act outside because of the high element of danger. The played Iron Man, which no doubt made Sharon happy, with the buzzes from electricity created by their instruments. Howie said TV might do them justice, saying that the electricity is tremendous live. Piers agreed, called it one of the most unique acts hes seen, and adding theres something there that I think could be a real Vegas act. Sharon asked for an explanation on how it works, and it devolved into a more technical explanation than anyone was prepared to hear. She then suggested a singer she knows who could sing Iron Man for them next time.

Prince Poppycock: The opera singer went from royalty to jester with a classic jester outfit for his singing performance. Piers said Prince Poppycock was becoming his little guilty pleasure and it was making him a little uncomfortable. He said the Prince can sing and has great stage presence. Sharon said every time she sees him, he gets more theatrical, which she loves. Its so refreshing to see an opera singer whos not fat and sweaty, she added, calling him perfect. Howie said the whole outfit was fabulous, its like Liza Minnelli if Liza was a clown. He said the question was whether middle America would respond to the act.

Murray: The illusionist said this was the biggest opportunity of his life and he couldnt afford to blow it. He had an assistant in a glass box and asked Piers for his jacket. He put Piers jacket on the assistant. He then pulled drapes over the box. He said America would be talking about the trick Wednesday, then pulled back the drapes to reveal a tiger in the glass box and the assistant appeared behind the judges table, scaring the heck out of Howie. The bald wonder called it amazing and Vegas and said, You wowed me. Sharon said Murray takes it up a notch every time she sees him and said he belongs in Vegas. Piers said the show usually doesnt get good enough magicians, and Murray is what Im talking about, in terms of the kind of magician the show needs.

Strikers All Stars: The stepping crew from Florida said this was the most amazing opportunity theyve had. They were prepared to take as many chances and up the intensity -- to the point that one of them got kicked in the face during rehearsals and needed stitches in his mouth. Howie said their moves in previous performances were more spectacular, and that another dance crew was a little more impressive. Piers said it was extraordinary that Howie made sense. He agreed, and said that Wednesdays results show would be a tough one because he thinks seven of the 12 acts from Tuesday deserved to move on. Sharon said it was unfortunate that they went last because the judges have seen everyone else already, and so the bar was set higher.

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