SpongeBob and Patrick are upset, because Sandy has gone to Texas for 2 days, they decide to throw her a welcome home party. During their party, SpongeBob and Patrick notice that Sandy is scratching and biting her fur. Sandy explains that upon her return from a science convention in Texas, she unknowingly brings back a flea. Sandy asks SpongeBob to open her briefcase and take out the flea collar. The flea jumps out of her fur and lands on SpongeBob. SpongeBob gets bitten and grabs the collar. The flea then lands on Patrick and bites him, causing Patrick to take the collar. They fight over the collar, then Sandy grabs the collar and wraps it around all three of them. The flea then reproduces, causing the flea collar to be eaten away, rending it useless. Fleas take over Sandy's treedome, and no one can escape the dome. Patrick blames SpongeBob for throwing the party and getting infected, then blames Sandy for bringing the flea. SpongeBob states they may be living in a sea of fleas instead of salt water, thus giving Sandy an idea on how to get rid of the fleas. Sandy was unique crashing into the cauldron with fleas by infecting all their space in the dome with saltwater, but all the Bikini Bottom citizens are stuck in the dome at the end.
When Patrick regurgitates Sandy's cake, it is in the shape of Texas.
The bus driver who hates SpongeBob's singing is Nat Peterson.
This episode possibly takes place before the episode "Squirrel Jokes," because in this episode SpongeBob doesn't know what fleas are. In Squirrel Jokes, he makes fun about how squirrels have many fleas.
Squidward was doing a power walk and said "Heel, toe, heel, toe" just like in "Bucket Sweet Bucket."
In 1 scene when the fleas make a face, the face resembles King Bowser Koopa, the antagonist of Nintendo's Super Mario Bros. Series.
The title is a parody of the play "A Flea in Her Ear".
When the flea screeches it has the same screech that a Godzilla kaiju: Megaguirus, screeches
Patrick can't possibly eat the apple from Sandy's tree since he is wearing a water helmet.
When Sandy said, "There is no such thing as vampires", the flea collar that SpongeBob was wearing was gone, and it came back when Patrick was about to take it from SpongeBob.
Patrick eats an apple from Sandy's tree, while the tree is obviously an oak. In a later scene Sandy even picks an acorn to throw at the fleas.
When SpongeBob says, "Glad to have you back, Sandy", the outline to Sandy's helmet almost disappears.
The fleas couldn't destroy the flea collar; it would kill them when they touch it.
It's impossible for Sandy's Treedome to empty the entire sea, with or without the mass of the Bikini Bottomites.
When Patrick talks about being bit by "vampire fleas", after he falls on the ground, his flea bites are gone.
Sandy states that the fleas are from Texas, but SpongeBob said earlier that Sandy went to Taos for a Science Convention. Taos is in New Mexico, not Texas.
Althouth, it is possible that while she was on the surface she took a short trip to Texas.
Another possibility is that Sandy lied to SpongeBob and went to Texas instead of Taos, New Mexico.
There should not have been any contrast between when there was water in the treedome and when there wasn't because the show isn't contrasted this way when the underwater setting is shown.
The collar keeps changing size when different people wear them.
When the flea hatches two eggs, more than three jump out. When one lands on SpongeBob, the top of his tie is white for a little time.