It's particularly creepy - and may be their best one yet.
Every year, we start to think that Neil Patrick Harris, David Burtka and their kids couldn't possibly make their Halloween costumes better.
And every year, like clockwork, they prove us wrong - but this year may be their best one yet.
The family opted for a Carnival of Curiosities theme for the group getups.
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The How I Met Your Mother actor was went all out, as he got decked out as a creepy ringmaster.
Meanwhile, Burtka fully jumped into this year's infatuation with terrifying clowns, with his eerie entertainer getup.
Gideon was dressed up as a strong man, compete with a teeny twisty moustache (of course), while Harper was dressed up as a flawless bearded lady.
The family are known for going all out when it comes to their Halloween outfits - and they always go in a group.
They went old school Hollywood for 2016, dressing up as Marilyn Monroe, Groucho Marx, Charlie Chaplin and James Dean.
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Meanwhile in 2015, they went as some beloved Star Wars characters - including Obi-Wan Kenobi, Princess Leia, Luke Skywalker and Han Solo.
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Other years included the family dressing up as Batman characters, including The Riddler, The Joker and Batgirl, as well as Alice in Wonderland the year before that.
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https://twitter.com/ActuallyNPH/status/528298961304817664
Image via Getty. 
