I'm going to leave a gross easter egg for my landlord to find when I eventually move out.
Why would you want your landlord to find an old gross easter egg?
It's his house now. He deserves to find it.
It's not right to purposely leave something gross for someone else to have to clean up. How would you feel if you were in his position?
I want to leave it, so I'm gonna.
Aside from it just being rude, think about the consequences of doing something like that to your landlord. When you move out, it's good to have a good relationship with your former landlord so that you can get a good reference. If you leave gross things behind for him, he may not give you a good reference.