stinkhorn
Explanation
This comic is a conversation between two people observing mushrooms in a forest, and it riffs on the intersection of biology and aesthetics.
One person comments that the mushrooms "look good with the weird stuff we see around here." The other person asks if they are familiar with stinkhorn mushrooms, noting that they are particularly impressive-looking but also that the fungus also has connections to some rather unpleasant biological realities. The conversation turns to how stinkhorns are known for their phallic appearance and foul smell (they smell like rotting flesh to attract flies for spore dispersal).
The punchline involves the observation that God (or nature/evolution) has produced some remarkably creative organisms, and then references the Clathrus genus (a type of stinkhorn), implying that the viewer should look it up to discover just how bizarre and unsettling these fungi can be.
The humor comes from the juxtaposition of appreciating nature's beauty while simultaneously being confronted with nature's more grotesque creations. SMBC frequently plays with the idea that the natural world, when examined closely, is far stranger and more disturbing than people casually assume.