Friend is an average-sized jellyfish with a blue body and seven navy-blue/dark-blue spots.
He is the stealthiest and fastest of every known jellyfish SpongeBob had caught, not to mention being the smartest jellyfish of them all due to his evasion maneuvers. He used to be called "No Name", until later at the end of "Jellyfish Hunter" where he was named Friend.
Role in episode
Friend is only seen in "Jellyfish Hunter", where he avoided being caught by SpongeBob. After being sent by Mr. Krabs to catch every jellyfish for their jelly and the population of Jellyfish Fields was depleted, SpongeBob is followed by No Name when going back to his house, where he is captured by the blue jellyfish when he cuts the electrical wire and lures SpongeBob with a Krabby Patty made from his own jelly.
No Name brings SpongeBob to a factory and shows him the inside where every jellyfish SpongeBob caught are being tortured and their jelly was being extracted. SpongeBob then sees Mr. Krabs in the factory and realizes he is the one who tricked SpongeBob into catching the jellyfish just for money.
The two of them storm into the factory, stop Mr. Krabs, and free the remaining captured jellyfish who proceeded to sting Mr. Krabs. As thanks for rescuing his kindred, Friend allows SpongeBob to catch him, and No Name was renamed to "Friend."
Like all jellyfish, Friend can create an electric shock/sting that makes the body parts of a hostile person to swell up. However, it is shown in "Jellyfish Hunter" that Friend can hold back his sting if, for any reason, he wishes not to harm someone, as seen when No Name taps SpongeBob on the shoulder while inside the factory. Friend also has the ability of stealth, speed, and intelligence. It is also shown that No Name is skilled at using a jellyfish net and a jar, therefore making him the smartest jellyfish.
"BZZ, BZZ, BZZZZZZ! [translated to "Bring it on!"]"
"[heavy breathing noises]"
In the Morris Broadband description of the episode, No Name is called Ol' Buzzy.
This is the main jellyfish along with the one in "Jellyfish Jam" that SpongeBob interacts with.