Its floating in the air by the left side of the lighthouse.
Big Nate Island's School Picture Guy said that he tried an ocean theme last year, but there was a fiasco. Fiascomeans sudden violent collapse, so there something violent must have hit that guy in the head.
You eat it.
The guy at the "Say Cheese" photo shop, who will swap you some scuba gear for it.
You get the keys from the lobster guy. Then you ride. Jump when necessary to reach the island. Be faster than Nate!!
Thinks he's cool: Big Nate on Big Nate Island. Cool but not to be trusted: Shady Guy on Counterfeit Island Director D on Spy Island
You have to assemble the comic strip from the frame (which he gives you) and the 8 missing pieces that are scattered about on Big Nate Island. (see related questions)
Inside the Klassic Komix shop.
Type your answer here... talk to him
you go to the picture place and show it to the school picture guy and he will trade it for scuba gear which you can use to go diving
On Big Nate island, you have to go into the Komix Shop, and talk to the guy, then find all of the Big Nate comic pieces, assemble them, and give them to him. Then he'll give you gum. *Various kinds of "effects" using gum are also available in the Store, but do not have anything to do with Big Nate Island.
You don't get gum from the picture guy. You get gum for finding all the comic pieces and putting them in the right order. When you do that, give it back to the guy in Klassic Komics and then you will get gum. The picture guy on the other hand, gives you a diving suit when you give him an old photograph that you find by the lighthouse. (see related question)
You don't just get the keys after you get the lobster and the scuba gear then the guy that wants it will give you the keys.