Mr. Krabs' 1 Millionth Dollar
Mr. Krabs' 1 millionth dollar is an ordinary one-dollar bill that appeared in the episode Clams which Scooter gave to Squidward at the Krusty Krab for Coral Bits. Mr. Krabs loved it because it is "every crab's dream to be a millionaire" and celebrated by bringing SpongeBob and Squidward on a clam fishing trip on the S.S. Cheapskate. The dollar is eaten by a clam named Old Blue Lips during the trip, but Mr. Krabs gets it back after trading half of his body with Old Blue Lips. Mr. Krabs calls it "me millionth dollar". SpongeBob and Squidward tried to trick Mr. Krabs into believing that they found his 1 millionth dollar by taking one of Squidward's dollars and giving it to Mr. Krabs. Mr. Krabs soon realized that it wasn't his 1 millionth dollar when he was doing his dance since it didn't feel right.
 First and only near-death experience
When the dollar was eaten by Old Blue Lips, it was a reference to the shark in the 1975 movie Jaws. Krabs was heartbroken, and made a grave that said "R.I.P. Me Millionth Dollar" and he then hugged it, explaining that for every type of currency Mr.Krabs loses and/or spends, he builds a grave for them. It was on the title card of Clams, a parody of Jaws, and instead of Chrissie swimming it was the dollar, and instead of the shark,it was the clam. It had the same music as Jaws.
It is green and looks like any regular ordinary dollar bill.