What kind of caterpillar is this and what does it have on its back? .?

I cannot see the pictures either but I suspect you have what is known as the "tomato hornworm" also known as "tobacco hornworm". It has what looks like a spike on its back. This worm lives in the soil near the stem of your tomato and comes out in the evening and proceeds to eat every tomato leaf it can eat. I have never heard of the spike on its back injuring anything but I would remove the worm with a pair of pliers and put the worm in a container it can't get out of. When you are looking for them in the evening you can often hear them making a clicking sound.

i think you should pick them up using gloves. (i can't see the pictures it said i should log on first)