She looks very similar to Squidward's temporary pet, Snellie. She has light blue and light green skin and a lavender shell. Her shell also has a dark purple swirl along with a pink bow. She has dark blue eyes and eyelashes.
Annette is seen stuck high in a tree somewhere in Bikini Bottom and is seen to be close to falling until SpongeBob rescues her. She is mentioned to have been in Mrs. Puff's possession since she was a little girl.
In the stage musical based on "The Sponge Who Could Fly," Annette's role and history are expanded upon. She appears as a live-action puppet during the song "I'm Flying." Mrs. Puff mentions that Annette had to get a shot at the local vet and was upset about it. It is also explained that Mrs. Puff was originally going to name her snail Antoinette, but the name was taken by her friend Claudette.
She later makes a cameo appearance in a photo in Mrs. Puff's house in "Spot Returns" and "My Two Krabses."
In a 2019 post from Nickelodeon Latin America, Mrs. Puff was incorrectly said to have Snellie as her pet, when she is actually a separate character.