Sky
Sky
[Megan is looking down at Beret Guy, who appears to be doing a handstand on a grass lawn, with grass tuft drawn several places, including where his hands touch the grass. His hands can be seen in the grass like he is holding on to the grass. Both his legs are moving around above him, as indicated by movement lines.] Megan: What are you doing? Beret Guy: Clinging to the ceiling of a bottomless abyss.
[Megan walks past Beret Guy, whose legs are still moving. She is still looking down at the grass.] Megan: You are very odd.
[In a frame-less panel, Megan walks towards a mailbox looking down at it. There is grass around the base of the mailbox pole.]
[As Megan passes the mailbox, she looks up towards the sky and seems to stop.]
[The last panel is upside down with the grass at the top and the mailbox pointing down. Megan is clinging to the mailbox, sitting on the grass with her head under the mailbox. Ponytail approaches her, walking on the grass with her head pointing down. The text is written in the sky below them.] Ponytail: What's wrong? Megan: I looked down.

This comic is about the fact that much of the way we see the world is relative. Which way is left or right, for example, depends on the direction one is facing, so different people can give different answers and both be correct. (Contrast this to absolute directions, such as East and West, which do not change based on one's orientation.)
Which way is 'down' is a little more complicated, as both the absolute and relative direction use the same word (owing to the two directions usually being the same on Earth): it can be defined as 'whichever way gravity goes / the direction things fall', but it can also be defined as 'the direction one's feet is'. In space particularly, the latter definition tends to be used as the former is rather hard to deduce. It is possible, though not too useful, to simply say that 'down' in space is 'whichever way Earth is', or perhaps even 'whichever way is opposite to the Sun'.
However, even on Earth, the direction of 'down' can get muddled. Humans rely a lot on vision to determine which way is down, so in an enclosed room with no references, one can easily convince themselves (accidentally or deliberately) that down is in a different direction to gravity. Forcing yourself to think in a different perspective changes a lot of things that are usually thought of as mundanities.
Beret Guy convinces himself that down is toward the sky. Megan asks him why he is clinging to the ground. He responds that he is holding on to the ground so that he does not fall into the sky. Megan at first dismisses this but later looks up, gets scared and is found by Ponytail , clinging to a mailbox afraid of falling up (down?).
The title text continues this idea, where  Megan "drops" a bird into the sky, and never hears it hit the "bottom". As birds can fly, and captured birds often fly away when released, its flight appeared to Megan as the bird falling upward. "Didn't hear it hit bottom" would normally mean that the pit is too deep for the sound of impact to make it back up, although in this case as the 'pit' is genuinely bottomless the bird would never hit 'bottom' even if it didn't move.
[Megan is looking down at Beret Guy, who appears to be doing a handstand on a grass lawn, with grass tuft drawn several places, including where his hands touch the grass. His hands can be seen in the grass like he is holding on to the grass. Both his legs are moving around above him, as indicated by movement lines.] Megan: What are you doing? Beret Guy: Clinging to the ceiling of a bottomless abyss.
[Megan walks past Beret Guy, whose legs are still moving. She is still looking down at the grass.] Megan: You are very odd.
[In a frame-less panel, Megan walks towards a mailbox looking down at it. There is grass around the base of the mailbox pole.]
[As Megan passes the mailbox, she looks up towards the sky and seems to stop.]
[The last panel is upside down with the grass at the top and the mailbox pointing down. Megan is clinging to the mailbox, sitting on the grass with her head under the mailbox. Ponytail approaches her, walking on the grass with her head pointing down. The text is written in the sky below them.] Ponytail: What's wrong? Megan: I looked down.
