yours
Explanation
This comic features a couple where the woman announces she's pregnant and the baby isn't her partner's. She says it's "genetically not yours" -- but the man immediately responds with "finders keepers!" and in the final panel triumphantly shouts "FINDERS KEEPERS!" while presumably claiming the baby as his own.
The joke subverts the typical dramatic reveal of infidelity during a pregnancy announcement. Instead of the expected devastation, jealousy, or anger, the man bypasses the entire emotional situation by invoking the playground rule of "finders keepers" -- as if a baby's parentage can be settled by the same logic children use to claim found toys. The absurdity lies in applying a childish, legally meaningless principle to one of the most emotionally fraught situations in adult relationships, completely defusing the tension in the most ridiculous way possible.