How do i summon on Two Worlds xbox 360?

I decided to play the game again and this time complete it. I have done pretty much everything but i cant seem to get the summon a creature achievement. I got all my magic to level 10 and now it says i need to get it to level 15? how? I have summon scorpion (level 4 water magic) but when i assign that and try summoning it all it does is heal. Im really stuck on how to work this magic. Can anyone help?