The ending of House Guest is quite difficult to interpret: Steven tries to repair the Geode with his healing saliva, and despite his regained confidence he fails. However there is no need to fear, as Greg quickly saves the day with a complex human tool: high-quality duct tape!
It shouldn’t be hard to understand why this explanation is a little hard to take at face value: the Geode is an enormous structure of hard stone which is containing an incredibly powerful force, and while that force is enough to widen the crack in the stone as Greg and Steven watch the duct tape is apparently enough to not just stop the growth of the crack but also contain the storm (which had been leaking into the surrounding area.)
The duct tape sparkled on Steven’s night stand, but then so did Greg’s van after Pearl fixed it—and she was giving a list of very mundane repairs she had done to it. That makes it a bit tough to be sure that the sparkles represented some kind of magical property being transferred to the duct tape, from Steven’s spit or from the sheer power of Greg’s belief (and what little hair he has left).
This mystery might never be solved. If it is, maybe we’ll learn where Steven’s healing powers went… But that’s a mystery for another week.
Following up on my comment in the “House Guest” podcast post, here’s the bit from GTCG (p22): “I’ve got healing spit! But it doesn’t always work. I healed Lapis Lazuli’s Gem, and I fixed Dad’s leg, but some things I just can’t fix. I think I get psyched out. Maybe it only works on living beings? I’m not sure!”
Obviously, we’re not sure either, but that was my theory that I had in the back of my mind through my initial watch and then I mentally committed to after “Catch and Release”.
Honestly, we don’t know how the Geode works, so we can’t be sure. It could simply be that because the crack was covered, it was able to stabilize, pressure-wise. Like, nothing we saw makes us believe that there’s any pressure coming outward from inside, because the gems were able to approach it. I mean, Greg was able to approach it without being blown backwards. The tape simply covering the hole was probably enough to mend it, at least for now.
I wouldn’t put too much thought into the sparkles, because it really honestly COULD just be an animation choice to symbolize that the tape is important to Steven. Then again, those same sparkles usually pop up around when Steven heals a thing, like Connie’s face when her eyes healed. But I’m not gonna put too much thought into this one, until they actually take the tape off and reveal it was fixed all along or if the crack is still there.
Like, they didn’t fix it at any point, really. They just covered the crack up, and the crack being COVERED was enough to stop it from spreading, despite that fact that the Geode didn’t seem to exude any pressure. It seems that simply contact with open air causes the storm.
My big theory relates to the Desert Glass. When the Desert Glass touches sand / earth, it activates and begins building. When the Geode, or whatever is INSIDE of it, touches AIR, it “activates” and begins making the storm. We don’t know if dropping Lapis’ Mirror into water would’ve let her control that water, but it wouldn’t be beyond reason to think so.
Really, putting a big honking Geode around an air-controlling Gem is really the only way to keep it from touching air.