Of Course We're Sending A Little Poo...
What would any decent passive aggressive/revenge list of stuff you can ship be without a little fecal matter?
The #1 thing to send on this list comes from PoopSenders.com
Starting around $16, you can send a quart of freshly collected animal stool and have it anonymously sent out to whoever you wish that experience on.
Is it disgusting? Yes
Is it cruel? Absolutely
Is it hilarious? You betcha... but it's not without risk. It's not exactly illegal to mail some poo to someone, but it is illegal to harass someone.
As with all of the items on this list, if the intent is malicious, there could be repercussions later down the road... It may say "anonymous" on the website, but there's a record kept of exactly 'who' sent 'what' to 'whom'... If things are truly bad between you and your ex lover, you might be better off just outliving them the old fashioned way.