There already is a mini Spider Jockey on this site (by jojesper), but I just don't like these 1 block mini spiders.

Spider Jockeys In Minecraft, if a spider spawns, there is a 1% chance that a skeleton sits on its back. If you kill either the spider or the skeleton, the other one will survive. If the skeleton rides the spider into water, the spider will drown. Spider Jockeys are dangerous because they can climb walls AND shoot arrows.

Note: If you find the spider's legs too long, just cut them shorter. Another Note: You may use the spider without jockey, but the skeleton does not work without its mount.

I hope you like it.