The green stuff is salad dressing. One of my friends had this a while back and I thought I had lost this photograph because I replaced my iPhone due to its camera being incapable of actually taking a picture. Apparently, I had backed up my photographs before going to the local Apple Store to have my phone replaced. Guess it pays to back up your files outside of your mobile device. Cheers!
(Also note the Oxford Comma in the title. Go Oxford Comma!)
Taken with iPhone 4.
Edited with Photoshop CS5.