We all saw Bill die in a fire along with Stanley, but is the triangle guy we all love to hate truly dead and gone? Take a look at this video I found on YouTube:

From the looks of things, we may indeed be meeting Bill again on a sunny day. We may not know when or where, but I personally think we may see Bill Cipher make his triumphant return. What say you guys?

5061406 Lets use this for crossovers but for the actual series I don't know

5061406 I swear to God at the end of the episode where the bus was driving I heard Bill's laugh. Like right at the end, it kinda sounds like it.

5061406 Axolotl is a Mexican salamander, strangely, BUT without the A, we can get an Aztec god. Yet, doesn't seem to make sense, since they are in Washington. Xolotl is an Aztec God of fire, lightning, sickness, and deformities. Perhaps he may have importance?

5061441
They are in Oregon. Also an axolotl can regrow parts of its body that are severed, including its head. That might mean that Bill will regenerate at some point.

5061462 True. And yes, I realized I screwed up saying they were in Washington.

5061406 I feel like Bill is still in Stanley's mind. If he (Stan) can still have his mind intact, why can't Bill?

5061406
Maybe put a spoiler tag on this.

5061406 "VHH BRX QHAW VXPPHU, SLGH WUHH!"

But seriously, while Mr. Hirsch has suggested interest in telling a new story of the Pines family and Gravity Falls some years hence, this summer has come to a close. While it will serve as fuel for many fanworks, don't expect an official extrapolation for quite some time, if that statue hunt doesn't turn up anything unexpected.