When you first meet them, bullies sell dreams
It is very common of bullies to sell dreams to their colleagues when they first meet them and then fail to deliver. They promise them of things they would do together and how much he/she would help each other at the workplace, but they never actually do what they promised. This makes the victim wonder if there is something he/she is doing wrong.
It is also possible that bullies could show potential employees the kind of tasks they would have to do during job interviews. However, the victims would realize upon joining that they would not be given the tasks they were informed about and were so excited to work on. The employees would be extremely demoralized and would start doubting their own abilities.
Meanwhile, more manipulative bullies will promise you promotions or raises to get you to work extra or promise you to get work that you really love doing but then never deliver on those promises.