The popsicle twins are two conjoined striped popsicles consisting of red, white, purple, and blue colors. They have a pointed tip on the top.
Role in movie
Plankton enters SpongeBob's brain to find the Krabby Patty secret formula. He enters a world of happiness and candy where most everything is sentient. During his time there, he hears the popsicle twins greeting him. He turns around to see them. They ask him to play with them and Plankton gets scared at the nice things in SpongeBob's mind. They say "Hurry, before we melt." He then becomes even more scared.
The popsicle twins start laughing as they melt, which causes Plankton to run away from them.
They are based of a Popsicle called "Red, White and Blue Turbo Rocket" or "Bomb Pop."
They are also a reference to the twins who hold hands saying "come play with us" in The Shining.