Customized version of http://www.thingiverse.com/thing:1995900

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=1995900

Using the following options:

spikes_variation = 5
pattern2 = bulb
pattern1 = spike
angle = 137.51
pattern2_every = 10
spikes_scale = 0.1
bulb_type = hole
spikes_distribution = Bigger_at_top