Printer going wild mid print Mid way through prints the print head will crash into the print, then crash into the bed, raise up about 3 inches, and start swinging back and forth over one part of the bed.

I have had successful prints with the same firmware, but this just started happening and I cannot wrap my head around why. The part of the bed it swings back and forth over is the same on every print. It also do not occur at any particular time, on some prints it will happen after the first few layers, on other it will happen mid way. 

My printer is an anycubic kossel delta running marlin. I have tried re uploading marlin and switching slicer software. I have used mattercontrol, cura and ultimaker cura.

Thank you!
For anyone having the same issue I found out it was due to a Z axis motor lock up because the pulley attached to it would get stuck under the bed. I found out because I tried to print again and it locked up completely and I had to pull it out with pliers. Just finished an 18 hour print to confirm