The term 'Cause of Some Brain Freeze' can be solved by the four-letter word 'ICEE'. ICEE is a brand of frozen carbonated beverage that is popular in the United States and other countries. It is known for its slushy texture and sweet taste, and is often consumed as a refreshing treat on hot days. The brain freeze sensation that some people experience after drinking an ICEE is caused by the rapid cooling of the mouth and throat.