corpse
Explanation
This comic is a wordplay joke built on the double meaning of "shotgun."
In the first panel, two people in funeral attire are alarmed to discover that the corpse is sitting in the passenger seat of the hearse rather than in the back. One exclaims, "Oh my God, the corpse is in the passenger seat! What's the point of a hearse?" The other responds, "The son of a bitch got us. Right before he died, he got us."
The comic then flashes back to "Earlier..." where the dying man is on his deathbed surrounded by family. Someone asks, "Do you have any last words, Papa?" and the old man shouts "SHOTGUN!" -- his literal dying word.
The joke hinges on the informal rule (popular especially in American culture) that calling "shotgun" gives you the right to sit in the front passenger seat of a car. The dying man uses his last words to claim the front seat of his own hearse, which is both morbidly clever and hilariously petty. The humor comes from the absurd image of mourners being honor-bound to respect a dead man's "shotgun" call, combined with the darkly comic idea that someone would use their final breath not for something profound but to win a silly car-seating game. It is a tight, well-constructed pun joke with a perfect setup-and-payoff structure.