This ridiculing on top of Lars' farm actually bringing a greater yield than Joanson's was why Ariq began plotting Lars' death. He had it all worked out, planning to have it blamed on his nephew, Luke Skywalker. Luke was at that age where he could go either way, perhaps even put on some black and shoot up the kids at his school. However, he had no school and half his friends had just split. This on top of growing up with no blood relatives around him could easily be used as the rationale for Skywalker killing his aunt and uncle. It made perfect sense.
One morning Ariq went over to the Lars' farm to finally act on this plan, but discovered someone had already beat him to it. Owen and Beru's charred bodies were lying on the ground, and Luke's Landspeeder was racing away in the distance. Ariq's jaw dropped. The punk had actually done it. He'd done it! And Ariq didn't have to do anything! It was a miracle!
Arix immediately went to Mos Eisley to celebrate in the Cantina. He was on his fourth drink when he saw Luke Skywalker walk in. Ariq panicked slightly. Had Skywalker seen him? Then Luke got into it with a couple of thugs, and all Ariq could make out was a lightsaber and some screams.
He had to get out of here. He'd heard rumors about Luke's dad being that nut who killed a bunch of Tuskens years back with a lightsaber. It was only a matter of time before he came after Ariq's Tusken-friendly ass.
Joanson got back to his farm, finding almost a dozen Tuskens waiting at the edge of his property with sorrowful and thirsty eyes. "Not today, I'm sorry!"
He packed his bags and jumped on his one-seater starship, the Wet Dream. Ariq took off and headed into the Wild Space area. No one heard from him again.