Ook will spawn at the lobby and proceed to walk through the rooms slowly, like a normal rusher, it will walk through the rooms and kill anything that doesn’t hide from it, it rebounds in a pattern most identical to A-25, yet considerably slower, it’s near sound is similar to gurgling, like simon. Due to Ook being a silent entity and not having screenshake, it is better to determine if Ook spawned by listening closely, if you can hear footsteps, you have a lot of time to hide, Ook's dad is G-575.