This happens early on in the movie and is not meant to have the same effect. Instead, this is done to create a strange, morbid laugh. At least, the first time. When they re-used this bit in Feast III (see my review to see what else they stole), it was just sad. I'm not going to focus on that one and instead focus on the good one (it's a relative compliment, really).
What they know: they were enjoying a beer or two in a desert bar when a tiny monster showed up. It caused lots of mayhem in a moment, including cutting off a biker's leg and skinning off Jason Mewes' face. Eventually, they get it locked in a soda cooler and think that everything is alright. Unfortunately, they are wrong- dead wrong. They learn that the monster they just stopped was one of the baby off-shoots of the real beasts. Fortunately, hope is here.
A burly young man ('McSteamy' from Grey's Anatomy) shows up with a shotgun and a barrel full of machismo (the latter bit is metaphorical, of course). He explains that if they work together, everyone will make out it alive. Evidently, he missed the two corpses on the floor. Right at the end of his speech, a monster's arm bursts through the wall and pulls him partway through. Faster than you can say 'I hated this in Zombie 5 too,' his body comes back without a head. This, of course, comes after the movie touts him as the hero of the movie who will practically live forever.
This movie is not that bad, although its low-budget is evident in the use of dark lighting. Even so, the tone is handled fairly well and the movie is pretty enjoyable. When it gets a bit darker (thematically), it is less fun. Did we need a scene of a wounded woman being raped by monsters? Not really. I've said enough about this series though, to be honest. I will just add more thing: that bullshit ending with the robot is still stupid. Who thought that was a good idea?!? Ahh, I feel better.
Is there more on the horizon? Why do you ask? Didn't you see me die earlier?!? If I come back, stay tuned...