One-Two Punchline

Twice is nice! Right?

A comic trope in which either the two last panels of a strip each contain a punchline, or the last panel contains double the punchlines for double the fun. May Cross the Line Twice, but doesn't necessarily need to. The penultimate panel is often a sight gag, and if this is true, then the last panel may add a spoken punchline to this.

Related to Escalating Punchline. For webcomics, Alt Text is frequently used as a way to convey the second punchline.

Examples of One-Two Punchline include:

Newspaper Comics

Often used in Pearls Before Swine, especially in the pun strips.
Calvin and Hobbes: Bill Watterson was fond of these, with Hobbes adding another punchline on the far right of the last panel, often a mockery or lampshade hanging on what Calvin was saying.
FoxTrot is fond of this.
Doonesbury was the first newspaper comicstrip to regularly use this, and was directly or indirectly the inspiration for most modern uses.
The "two punchlines in last panel" variation is frequently seen in Cul De Sac.

Web Comics

Sometimes in Questionable Content, as seen here.
In an example from Bob and George, after Bob revives from unconciousness off panel, when he actually appears in the penultimate panel of the next comic, he is wearing a ridiculous girly costume. The final panel has him making a reference to the prior Halloween comic, which is where the costume originated.
Cat and Girl uses a fairly standard size format for its comics, but sometimes there will be an extra panel or two drawn in grey that adds a punchline.
The Order of the Stick does this quite a lot.
Many web comics (including The Adventures of Dr. McNinja, xkcd and Achewood) will include secondary punchlines in hover-over alt-text. Saturday Morning Breakfast Cereal and Amazing Super Powers go a step further, including an entire bonus second-punchline panel, the former by hovering over a red button at the end of the strip, and the latter by clicking a hidden question mark at the comic's side.