Badluck Schleprock
If your looking for the negative character on the Flintstones call "slep rock" his real name is Badluck Schleprock. You can find some information on Wikipedia. I haven't found anything that actually shows what episodes that he appeared in.
I am blogging this because I had a hard time finding the character base on my search for "slep rock" and the name wasn't listed among the characters on the main Flintstone page on Wikipedia. My search found other people had the same problem spelling Schleprock's name.
Hope this posting helps someone else out! Poor Schleprock, stuck with a name that many people can't spell correctly.