Often, Usagi cannot get into places where she needs to investigate evil activity. These places may only allow authorized personnel, people with tickets, or there may be an age restriction. In order to get past these obstacles, Usagi uses a special transformation pen with which she can disguise herself.
Who uses it?: Sailor Moon, Sailor Venus
Luna gave Usagi the disguise pen in episode 003 so that she could get past a security guard and enter a the FM No. 10 studio to confront Jadeite. After this first appearance, Usagi used the disguise pen for ten different disguises in the first and second seasons. She usually used it for reasons related to her mission... but she sometimes used it for purely personal reasons as well. The only other senshi to use the disguise pen was Minako, who disguised herself as Sailor Moon in episode 102 in order to protect Usagi's identity. In order to transform, Usagi said the transformation phrase followed by a brief description of what type of person she was transforming into. Although she was disguised in everyone else's eyes, the other senshi were able to recognize her immediately. She also apparently took on the skills of whomever she transformed into, such as being able to pilot a boat after transforming into a sailor in episode 042.
Sailor Moon's anime disguises