BJT Ic vs VBE graph in Proteus simulation
Well, I guess if the base voltage exceeds the collector voltage the transistor is sort of in saturation, so you'd expect the collector current to level off. 

However, putting +100V (or even +10V) on the Vbe junction of a transistor is so far outside of normal operation that you can't expect the models to do anything sensible. In reality the transistor would be a smouldering crater just about instantly. 

The "leveling off" occurs at a power dissipation exceeding 150W, on a part capable of a watt or two.