skyjedi2005 said:
Slimer survived you can see him in the end of ghostbusters 2 which was supposed to hint there would be part 3.

Actually, he's all over Ghostbusters 2. He's in the montage in the middle of the movie. He drives the bus that takes Louis to the art museum, and he's listed at the end of the main character sequence at the end. His appearances can actually be attributed more to the success of the character on the cartoon series (where the name Slimer originated) rather than a look forward to Ghostbusters 3 (Aykroyd and Ramis only did #2 under duress).