Laughter
a demonic manifestation
or
a reaction to nothingness
amico:
Maybe a bit of both 
,that's what it is for me any way HMHMHMHWAHAHA!!...lol.
,that's what it is for me any way HMHMHMHWAHAHA!!...lol.
dancerman:
To me it looks like you have some sort of mischief in mind and woe to any nearby innocent bystanders...