I'm a fan of Chad Carpenter's Tundra strip. This one is a variant on the "the character is unaware of something" sort of joke that was also exemplified in our first installment in this series. Carpenter tells his whole story in one panel and with only one character, but the basic premise is the same: the reader is aware of something the character is not, and the basic humor emanates from that.
Carpenter spruces up the gag a bit with the character's line – the "nibble" he felt is clearly a massive understatement in relation to the giant bite that just led to the disappearance of not only his fishing buddy, but the entire rear half of their boat.
(Note the hat from the fishing buddy floating in the rubble – it is there to inform you, the reader, that this isn't some crazy person talking to himself but rather a normal person who simply doesn't know there's nobody left to listen to him.)