Mario
Mario
Megan: For our anniversary, my boyfriend took me hiking in the mountains. Ponytail: My boyfriend proposed to me. Ponytail: They should call you Mario, 'cause you just got <<1 up'd.>>

One-upmanship is the act of surpassing another person. In this case, one female character is one-upping her friend's claim of being taken on a mountain hike with a claim that she was proposed to.
Mario is the major figure in the Super Mario series. In the games, completing specific conditions causes a "1-up" (but the marks are chevrons («»), used in some languages like Russian instead of quotation marks) to appear on screen, referring to an additional life. The comic relies on the homonym of the action of one-upmanship and the event of one-ups in Mario.
In the title text, Randall implies that this is a pretty bad joke.
Megan: For our anniversary, my boyfriend took me hiking in the mountains. Ponytail: My boyfriend proposed to me. Ponytail: They should call you Mario, 'cause you just got <<1 up'd.>>
