Boss StreuneR (also known as upper Streuner) are a boss version of StreuneR are 4 times stronger. Like the StreuneR, they will fire on passing players. They have a visual difference when compared to the normal StreuneR, in having a slightly bigger alien ship. They can be compared to Boss Mordon but with slightly faster speed. Unlike regular StreuneR, once a Boss StreuneR's shield is down, it will reverse the way your ship flies. This can be annoying when farming multiple Bos StreuneRs. Therefore, your movement isn't reversed while flying to collect something, like cargo, bonus boxes, etc.