NASA send their team to investigate a new planet, PLANET X. The film starts with the crew leaving the planet in their spacecraft. We see them shutting the door to their spacecraft, however the door gets stuck on something, after slamming it a few more times, it closes. What the crew don't realise is that an invisible blob has just boarded the spacecraft while they were leaving.
A NASA conference follows We see the Director of NASA announcing to reporters that their crew have arrived safely from PLANET X and have retrieved valuable information, however before he finishes his sentence we see him get wrestled to the floor by 'something'. Then, a few members of the conference get thrown to the floor, and the whole room begins to panic.
We then cut to a TV screen that shows a News Channel with the reporter saying something along the lines of "Mass panic in America, as an unidentifiable creature attacks humans, everyone is warned to stay indoors and keep all windows and doors shut!"
The astronauts take it upon themselves to destroy the blob as they feel guilty for letting it on board in the first place. They use all sorts of instruments to attack the blob.
As the astronauts attempt to kill the the blob, researchers begin to research the data taken from PLANET X. They find that the answer to killing the blob, lies in the information they have gathered from the planet. A mineral in the rock from PLANET X, is the key to the blog being seen/destroyed.
Ways of making this funny:
When the blob takes over the Director, it could make the director slap himself a few times.
A victim of the blob, could be someone who's eating jelly. We see a tear on the blob's face, after a spoonful of jelly is eaten.
At the end, the blob is frozen, and sold as ice lollys.
The blob could meet a Snail and say "look what they've done to you! They've made you carry that giant rock on your back!!!".
The blob, at the start, it's visible but can become invisible at will. We see the blob with it's angry smirk on its face as it makes it's way into the space craft, but when it gets hit by the door it goes 'ouch!'.