In the original anime Shingeki no Kyojin (Attack on Titan), there was an OST playing at 18 minutes and 40 seconds into the first episode. This OST happenned when Eren Jaeger saw the Collosol Titan for the first time before the latter smashed a hole into the outer wall. What was the name of that OST/song in the background? (If the song name is a part of a bigger OST name (aka Difficult OST from One Piece being made of two parts, Shichibukai and Mr. Prince), could you name only the specific half of the OST? Thanks.