Grian's Time Machine is the driver of the Area 77 Story Arc. Grian originally created the Time Machine to retrieve his lost/stolen diamonds and Villager Grian.
Present Grian goes back in time to take his lost diamonds and Villager Grian back from Past Grian. Past Grian believes that they have gone missing, and will use a time machine to take them back. The loop explains that the diamonds and Villager Grian were never lost, but stolen by the future version of Grian.
Area 77 Capture
When the Time Machine reappears in Area 77, Docm77 and GoodTimesWithScar take it and hide it in the underneath Grian's Bikini Bottom build. The disappearance resulted in the formation of the Hippie Group and the plan to retrieve the Time Machine, along with Renbob's (Rendog) RV's nuclear reactor.
Transfer to S4
Grian, Rendog, and ImpulseSV use the time machine, in Sector 4, to escape Area 77. Unfortunately, it misfires because Grian forgot to put on a compass, and it teleports them to "HermitCraft Alpha", a server in Minecraft Alpha. The Time Machine disappears and they are forced to go through the difficult journey to collect resources to create something pretty similar to the original time machine, as many of the blocks that were used were not available in Minecraft Alpha. They successfully recreate it and use it for the last and final time.
Deemed too dangerous, the trio destroyed the Time Machine using TNT, ending the Area 77 Story Arc.