Snail-Po is a brand of snail food which is not recommended for any sea creatures other than snails to consume. It first appears in the episode "Missing Identity."
Snail-Po is used to feed the snails of Bikini Bottom, but most snails do not seem to enjoy the food, including Gary, as seen in the episode "Have You Seen This Snail?" (though, he is still seen eating it or at least willing to). Gary would much rather eat cookies and nachos, and the comic in the Nickelodeon MagazineAll-Animal Special shows that he wants only the finest foods possible.
The product is first seen in the episode "Missing Identity" and has an awful taste according to SpongeBob after tasting it, causing him to let out a loud "Blech!" which echoes through the town to the Snail-Po headquarters. This is likely due to him not being a snail.
There is a Snail-Po headquarters, as seen in the episode "Missing Identity." It is located somewhere in the downtown area of Bikini Bottom and looks like most big corporate companies. Nat Peterson is most likely in charge, and one of the two people in the company who talks. When SpongeBob vomits upon tasting the Snail-Po, his cry reaches the headquarters. Peterson hears him and when a woman in the company asks what is wrong, he says "I'm not sure, I feel... a disturbance."