hole
Explanation
This comic parodies ontological arguments -- philosophical debates about what kinds of things "exist" -- by applying them to food items, specifically donuts and donut holes.
In the first two panels, a bow-tied character (suggesting an academic or philosopher) makes a seemingly logical chain of reasoning: donuts exist, and donut holes exist. The other character reluctantly agrees at each step. The philosopher then extends the logic: if any food served in the form of a ring implies the existence of a corresponding "hole" form, this should be a general principle.
The other character erupts with "IT DOES NOT!" -- rejecting the absurd generalization. The final panel, labeled "Earlier...", reveals what started the whole argument: the bow-tied character had invited someone to "munch some squid holes," applying the donut/donut-hole naming convention to calamari (squid rings). The joke is that calamari rings are structurally identical to donuts -- they are ring-shaped food -- and so by the same logic that gives us "donut holes," we should also have "squid holes."
The humor comes from the collision of formal philosophical reasoning about ontology (what exists, what categories are real) with the mundane world of snack food. The philosopher is technically making a valid analogical argument, but the conclusion is so absurd and unappetizing ("squid holes") that it provokes visceral rejection. It also pokes fun at how philosophical arguments about existence can sound perfectly logical step by step but lead to conclusions nobody would accept, which is a common feature of reductio ad absurdum arguments in philosophy.