It is a large boat-shaped bubble that is transparent.
Role in episode
When SpongeBob is showing Patrick various bubbles from his technique, he uses his left hand to blow a bubble on his bubble wand to create a large boat bubble. Patrick enjoys watching SpongeBob blowing the bubble until the bubble ends up popping right outside of Squidward's house, making a huge foghorn sound. As a result, Squidward thinks that the sound came from his clarinet and he shakes it.
- This bubble makes the same foghorn sound as SpongeBob's alarm clock when it pops.