Over the Edge

How this card works

For 3 Eddies, Over the Edge defeats a Unit whose power is equal to or less than the value of a friendly d20. A high roll can remove almost anything on the field, whatever its cost or colour.

Everything depends on that d20. Per the FAQ, without one in your Gig area you can still play the card but nothing is defeated, not even a 0-power Unit. A d20 you stole from a Rival is friendly once you control it. To lift a low d20, Industrial Assembly increases a Gig by up to 4 for 1 Eddie, and the Spend on Dexter DeShawn: Off the Grid increases one by up to 2.

The card says "a Unit", not "a rival Unit", and the FAQ confirms you can defeat your own. That can be a way to set off one of your Unit's defeat triggers on purpose.