An alien ship causes a tidal wave and ruins civilization

I'm in Wilmington at the college. The coach figure I can never directly see tells four of us to go take cold showers and come back naked. On the way to the shower, a girl falls into a huge dirty toilet and as I'm hesitating to reach in and help her out, somebody else does.

I take a cold shower and return. The coach tells us to sleep directly on the floor with our heads pointing north. I suspected this was what he was going to have us do. He thinks north is a bit of a different direction than I do, I correct my position and ask why we're doing this. He tells me it will bring "good fortune to our ambassador."

Suddenly, a gigantic smokestack - miles and miles long - arches up and falls again over the ocean beyond the horizon. A second later, an even larger and more rocket shaped object does the same. Someone asks, "should we worry about a shock-wave?" I yell, "Tidal wave!"

A tidal wave hundreds of meters high approaches and engulfs everybody. I time holding my breath. Everybody is pushed miles and miles inland, the coast is flooded. We appear to be in a series of large underground rooms.

There are groups of aliens, which have heads like dogs and bodies like fish and swim through the air like fish. They are not very intelligent and mostly a nuisance because they always want to nip at you, half aggressively and half playfully. Civilization is ruined and we'll have to exist on canned goods, etc.

I decide to befriend one of the aliens and am surprised at how little effort it takes. I ask him if he can help us rebuild civilization. "No, but we can un-flood the coast." A men overhears this and excitedly asks what the alien needs. The alien says he just needs to go back to the ship.

A party of us return to the coast. We're waiting while the alien is off beyond the horizon. Suddenly, another tidal wave comes. Again, I hold my breath and everyone is washed back to the underground room. Someone expresses anger that the alien just caused another tidal wave and only made things worse. The alien gives me three film canister sized containers with a little moist black sand in the bottom of each. Everyone somehow suddenly knows, or thinks, that the sand is a cure for our predicament. I get some of the sand on my lips by mistake, it's uncomfortable.

A woman says, "The dose is is two grains!" Everyone starts eating two grains of the sand. I'm alarmed because I don't know what the sand will actually do and decide to wait to see what it does to others as I try to wipe it off my lips without getting any in my mouth.