Marcus walks on his tiptoes and amuses himself by dumping liquid from sippy cups and containers.

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On occasion the TSA has expanded the list, as it did after a liquid bomb scare in August 2006 when it prohibited bringing large containers of liquids and gels on board aircraft.

CNN: March 7, 2013 -- Updated 0312 GMT (1112 HKT)

On occasion, such as a liquid bomb scare in August 2006, the TSA has expanded the list, banning large containers of liquids and gels.

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