To be in a state of uber or uberness. The word uber is commonly used to describe one particular action or event, whereas uberem is a sequence of uber events one after the other.
>>> Surfing Context: "fuck, you were in a state of uberem on that wave man... I thought u were done for after the cutback, but you managed to get slotted
, exit the barrel and air off the back. hectic shit"
>>> CS Context: "yeah not only did I get a head-shot through double doors, I ran through long, wasted 6 cunts with my deagle then planted at A... I was in uberem"