Who is moving the coral in my reef tank?

[RuGlu6]

I had small colony of Candy Cane positioned by the back wall but it would always get moved and some time to a good distance away from original spot.
One day it was thrown half a tank across from where i put it.
I set up a car dvr to catch it in action.

Anyone wants to guess what is moving this coral?

Here is the livestock list:
Large French Angel
Hippo Tang
Two clown Fish
Two yellow Gobies
Coris Wrass (juvenile)
Large Strawberry Crab
Large Bobbit Worm

Mistery solved ! I know now.
Just wonder if anyone had similar experience.

Will post the video tomorrow.