YIKES, that is scary.  Keep us posted.

I messed with my older boy pretty bad re: the black tongue.  Any time they would lie when they were little I would say, "Stick out your tongue......BLACK!" the same way my mom used to and they believed it for a bit....but by age five smarty pants the elder did not buy it a bit. 

Then one day I happened upon these HORRID black jelly beans that indeed did turn your tongue VERY black, so I chewed some up and then told him, "Son, I am not really your mother..." then stuck my tongue out and man did he jump!  Then I dashed into the bathroom and brushed it and came back out and confessed I had lied (once again showing the pinky goodness of the truthful tongue).

It was too funny.