The Black Widow

The Black Widow is the anonymous character that made her first appearance in 'A' is for A-l-i-v-e. After a fan, suggested the name The Black Widow, Marlene decided to keep it.

Season 4
'A' is for A-l-i-v-e

The Black Widow attends Darren Wilden's funeral. She is shown to be wearing the burned Alison Mask, and is apparently a member of the "A Team". Earlier a mysterious person is seen fleeing the lodge after Spencer figures out that she and Toby are not alone. It could have possibly been Black Widow since she had the burnt mask. ('A' is for A-l-i-v-e).

Turn of the Shoe 

Mona gets in her car, and right after, she is attacked by the someone in an Ali mask who was hiding on the back seat; this may or may not be The Black Widow. If this is her, she may have gotten a new Ali mask because it isn't burnt on the side.

Possible Identities
Eliminated Suspects (people already in attendance at Wilden's funeral)
 * Alison DiLaurentis
 * Red Coat
 * Ashley Marin
 * Melissa Hastings
 * CeCe Drake
 * Paige McCullers
 * Dr. Anne Sullivan
 * Shana
 * Meredith Sorenson
 * The Liars
 * Mona Vanderwaal
 * Jessica DiLaurentis
 * Jenna Marshall
 * Pam Fields
 * Maggie Cutler

Trivia

 * Marlene originally  named her The Lady in Black.
 * After a fan, suggested the name The Black Widow, Marlene decided to keep it.
 * She was given the" fan-name" Veiled Griever because she attended Wilden's funeral, and she is 'grieving' the loss of someone and she has a veil on.
 * Based on the burnt mask, The Black Widow appears to have some connection to the fire.
 * The mask is A's mask so it may be Red Coat in disguise. If this is true than the burnt mask signifies that Ali may not have been Red Coat and pulled them out of the fire; she is someone the Liars haven't figured out.