Episode Description: Beware, spoilers! To read - hover over the text.
Scott and Allison are looking for a bestiary of her grandfather, where there should be information about the new creature. At the same time it is attacking Stiles and Derek in the school pool. Grandfather of Allison, realizing that Scott is a Beta, attacks him with a knife, a knife into the body of Scott, threatens to kill his mother if Scott doesn't accomplish what it will require.