Time machine from Chrono Trigger. At first only able to travel through time until Dalton, an overzealous emperor from 12000 BC steals it and puts wings on it, dubbing it his "Aero Dalton Imperial". The machine then becomes a transportation device for 4 dimensions (x, y, z, and t). In the end of the game the group is given the option of crashing into Lavos with the Epoch in order to make the final battle easier.

Also, the Epoch can be found, destroyed, in a secret room in Viper's Manor in Another World in Chrono Cross, along with a name-changing creature that I think is meant to be a Nu. Need a hint? Check the prophet's room.