Like BD2K3's laser, and just as irritating ;-)
Has four directions (and return direction), may be used as a movable wall (so it doesn't return)

1. Kills the Snake, anywhere on it's body
2. Kills all enemies
3. Indestructable
4. Activates Doorway switches (waits for the Doorway to close before returning)
5. Activates Level Door Switches
6. Explodes Bombs
7. Explodes Fuel Bombs
8. Moves Rollers
9. Moves Footballs
10. Moves Wood Blocks
11. Moves Light Blocks
12. Turns Steel Gems to Gems
13. Stopped by a Rebounder
14. Destroys Deflectors

The next items can't be moved by the Snake, so it's up to the level editor.

15. Waits until Time Bomb has ticked down
16. Destroys Static Bombs
17. Wipes Red Mushrooms (useless?)
18. Destroys Bubbles AND ocupant.
19. Waits for Candy Cane Door to be opened
20. Waits for Level Door to be opened