In an episode of season 4 of Grimm, we’ll meet a new wesen, Gedächtnis Esser (or Octo-Man). As you can see from the first look and picture, this creature is “a nefarious new Wesen who can attach his tentacles to your head and steal all your memories, leaving you either dead or with severe amnesia.”
One of his victims will be new Grimm in town, Trubel (Jacqueline Toboni). David Greenwalt, cocreator of Grimm said “This guy is ruthless and sophisticated — a high-tech spy who is involved with some highly placed military intelligence personnel”.
Source: TV Guide
Also, Bitsie Tulloch posted on her twitter account the script cover of episode 402, titled Octopus Head.
— Elizabeth Tulloch (@BitsieTulloch) July 23, 2014