The 'Woo' Guy refers to a specific Nightjar Ninja in the 2019 action-adventure game Sekiro: Shadows Die Twice. As players traverse the rooftops of Ashina Castle, this enemy suddenly launches himself from a kite with a high-pitched, echoing 'Wooooo!' scream, crashing into the player with immense speed. This moment became an instant classic jump scare and viral sensation within the FromSoftware community. The meme is typically used to represent anything that arrives unexpectedly and with high energy, catching someone completely off guard. It perfectly encapsulates the feeling of a sudden, loud interruption to a moment of peace.