Numbers 0 to 255 are reserved for engine use, although not all of them have events associated with them, and the rest can be used for any purpose.
A few of the more common reserved script numbers from the Creatures Evolution Engine are listed below:
|1||Activate 1 (Push)|
|2||Activate 2 (Pull)|
|4||Pickup (by something which isn't a vehicle)|
|5||Drop (again, by something which isn't a vehicle)|
|6||Collision (with a room boundary)|
|9||Timer (see TICK)|