The Hourglass

The Hourglass was introduced in the Pilot, its only appearance. The Crystal Gems have been protecting it for a thousand years. It takes the person who first activated it back in time for its chosen purpose only, and Steven used it for comebacks.

Powers
The Hourglass allows time travel. For 1000 years it was not active. Once activated, it can take back its owner in time so they can change the past for what the initial use was for. In Stevens case, it was comebacks.

First Appearance
Only Steven used it two times in Pilot. The Hourglass is activated after Steven's conversation with Lars after he left the Big Donut, offended by Lars' comment on Steven "not being a hot girl." With the Hourglass in his pocket, Steven thinks of a good comeback and wishes he could have said that. The magical item takes him back, but he is embarrassed again after Lars calls him a joke, so Steven repeats the process and leaves. The activation of the Hourglass attracts a huge Electric Skull. Garnet knowing they can't win she calls Steven a "buttface." He is first confused but during the fight he realizes she said that just so he can make a comeback and travel back in time. This way Steven knows the moves of the Electric Skull and they defeat it with the Big Doughnut on the top of the shop named after it.

After the fight Steven wishes he could have told Pearl he will save her life after she called him a clown, but immediately regrets it as the Hourglass takes him back in time yet again. The angered Steven breaks the Hourglass, however it still exists in that timeline, because Amethyst hasn't given it to him.