HALP!

I need ideas for a prank Christmas gift for my brother in law.  A brief history:

It all started when he got me something that I cannot remember as a gag gift.  I then got him a disposable loo and some big damn drawers (size 100 or so).  He responded by purchasing me a shirt that had arrows pointing to the biceps and says something along the lines of "guns this big," or something.  Anyway, I hear tell that he has purchased something for me already in the gag gift category that is damn good.  I cannot and will not let him win this competition, not when I have all you VOX Peeps to halp me.

So, if you would, please give me some gag gift ideas.  The dirtier the better, but keep in mind that his mom will likely see the present.  Heck, the dirtier the better.  All I could think to buy him as of now is a tub of that Sam's cake icing that is like 100% heart attack.  It would be a gag alright, but he would eat the whole damn gallon. 

HALP!