The ones in Armed and Dangerous were clearly supposed to be silly. They involved the land shark launcher, which launched a shark that swam through the ground and then burst out and devoured your enemies every few seconds.
There was also the fish gun in Half-Life: Opposing Force. I don't remember what it was called, but you straight up picked up a fish alien off the ground, and it shot out these yellow eggs, and kind of functioned like a fast-loading rocket launcher. The silliest part was reloading it. Your hand came on screen from the left holding the eggs, the fish bent over to the left and opened its mouth, and you fed it these eggs one by one, complete with the requisite "OM. OM. OM." noises.
What the hell are you pushing on to get it to spit out those eggs?
Great weapon, though. If you collected all the treasure clues, that is.
