Chocolate syrup is a condiment that only appears in the episode "Valentine's Day."
Chocolate syrup is, as its name suggests, chocolate made in a syrup form. It appears to have much of the properties to bubble mix, except chocolate syrup is just as edible as normal chocolate. It comes in a black bottle with a purple label that reads the word "chocolate" in white letters outlined by dark red, and the word "syrup" in dark red letters.
Role in episode
It is used by SpongeBob to bubble-blow chocolate in a way similarly to blowing bubbles with bubble mix. He uses the chocolate syrup to blow a chocolate heart to give to Sandy as a Valentine's Day gift and he also uses it to give a simulated plan of how to give Patrick his Valentine's Day present.