Seizures
There are many types of seizures. The ones people usually have in mind are convulsive seizures where people lose consciousness while their bodies go stiff and start jerking and moving violently. However, this type of seizures is not common in brain tumors. Other types of seizures might not involve a complete loss of consciousness but instead a sudden absent-mindedness or stiffness without jerking, and many others. These are more commonly found in brain tumors compared to tonic-clonic seizures.