Sudden Appearance/Disappearance of the Joker

Somehow, the Joker manages to appear and disappear wherever he is needed or subsequently forgotten.

Appearances
 * Finding Cate to break Sheridan out of Arkham
 * Taking care of Sheridan's house while she is in Arkham
 * Cate and Izzy's trial
 * Tormenting Crane
 * Staying with Cate

Disappearances
 * Attacking Julia
 * Kidnapping Gordon
 * Leaving Cate's Apartment