[Rob!]

First night, "The twist with no twist."

After all the housemates are in, one of them gets called to the Diary room. All this housemate does is receive a welcome pack, but Big Brother is actually using it's own Launch Night format to fool the others into thinking that something IS going on. Throughout the first week, housemates are given apparently suspicious stuff to do, called to the diary room often, made to do weird things in apparent secret missions that are never revealed to the house, all to make them ultra suspicious of each other. Nothing is ever revealed to them that nothing was ever going on, until they maybe choose to talk to each other about it (As with no secret missions, there will be no "this must not be discussed with your fellow housemates rule).
That would seriously mess with their heads

Some people on here should work for the show tbh