Boyz II Men Perform Tribute To Barney After The Fourth Slap on 'HIMYM'

Marshall went all out for the fourth slap on "How I Met Your Mother." He first set things up by telling Barney the story of his training at the hands of three slap experts -- they looked suspiciously like Robin, Lily and Ted -- to build anticipation. By the time the slap was upon them, Barney was appropriately anxious and terrified.

When it went down, it was certainly a powerful slap, but moments afterward, everything was great again between the friends. Then, the slap itself didn't turn out to be the highlight of the episode. The half hour had already been filled with plenty of nonsensical moments that made no rational sense, so why not add to the fun. For no reason, Boyz II Men came out and performed "You Just Got Slapped," while Barney sat there with a red handprint on his cheek.

“One slap remains! Where will it be deployed?" asked Entertainment Weekly's Katie Atkinson. "It almost has to be on Barney’s wedding day, doesn’t it? And will an even bigger band cover ‘You Just Got Slapped’ for the occasion?”

The countdown to the series finale of "How I Met Your Mother" continues, Mondays at 8 p.m. EST on CBS.

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