BHG shows up (Time traveling theory connecting comics #1190 & #1191)
One possibility is BHG, known for having traveld through time ("Kill Hitler", 1063), becomes inspired to do so, yet again, in "Time's" (1190) following comic "The Past" (1191).
Perhaps having to build yet another one-shot time machine to visit the pre-industrialized past — counting on easily drilling for oil in a foreign country since any opposition or military involvement would not yet exist. The panel has a conspicuous cold-open, and ends with BHG's words trailing off in thought with a schemingly sounding, "Hmmm...". The alt-text also feels particularly foreshadowing to this theory.
At some point, in a future comic, we should see BHG vanishing into the past, and excitingly, he appears in the previous panel "Time" coinciding with the very next newpic.
If so, we'll have had the luxury to see how The Past has been unfolding in all these interveining newpix in "Time" (1190), understanding what BHG will not be prepared for. Assuming typical BHG fashion, he's underestimating the past's outdated military, because Cueball and Megan have certainly been busy: Building sandcastles; using a trebuchet to destroy them; creating mounds to try and get a better vantage of their surroundings; creating a small scale layout of their newly created structures to use, as a military general might, to plan a seige on a war room table (and even placing a miniature trebuchet within it!).
We also get to see subtle clues in leading up to all this. They decide go for a swim in perhaps less than ideal sea water, causing Megan to choke and cough a little. Could it be tainted with crude oil? Also, Megan, pensively observing the sea level, doesn't seem to understand the rising tides, and Cueball remains silent. Suggesting this scientific knowledge must be after their time? They come and go as they please, playing, building, and experimenting, until Megan, probably thirsty or needing to bathe, asks where the river is. Most likely due to not having modern conveniences such as plumbing? Also, this would indicate an arid, desert climate with fresh water levels rising and falling in regions of the world now known for massive amounts of crude oil and fossil fuels not far below the ground.
And finally, Cueball, reaching the limit of his inventiveness, believes their creations can't be built any bigger or taller. He leaves Megan seemingly challanged by this departing declaration, and immediately puts her proven ingenuity to work, attempting something much grander which Cueball couldn't conceive.
If this theory plays out, BHG might arrive unwittingly too late, (as in the comic "Kill Hitler" ), where he succeeds in killing the Führer, but foolishly does so in 1945, near the end of WWII, making it totally pointless and wasting his one-shot time machine.
In theory, by the time he arrives in "Time", he should be in for quite a surprise when he finds out what Megan and Cueball have been up to...