To unlock this trophy, you need to score a total amount of 18 goals in Dropshot.
From the lobby in the game, press "Play", go to "Custom Games" then press "Exhibition". Change the settings so it matches this:
Gamemode: Dropshot
Map: Core 707
Team Size: Doesn't matter at all
Difficulty: No Bots
Then press "Create Match".
This trophy can take some time depending on how fast you can score these goals, but my recommendation is to put boost into it to create a powerful orb, you can hit it even more to create an even more powerful orb, it is really hard on how to explain this orb. Anyways, if that touches the opponent's floor it will damage it, after two hits the floor(s) begin to break. Allowing the ball in will give you one goal. This took me about 4-5 matches, it shouldn't take you more than half an hour to get this.