You have to admit, we're terrible tenants.
<spoilers for the hard-to-understand>
If you're looking at this and still having trouble figuring out what's happening, Earth is under attack by aliens. A nameless scientist and his nameless assistant develop a fighting robot named Protecto-boy and send him off with the command to defend earth by defeating its enemies. Unfortunately, there was a semantic misunderstanding and Protecto-boy identified mankind as the greatest threat to the planet, though not incorrectly.
If any of you are thinking you've seen this punchline before, you were probably thinking of Space Girl Ultra Marin
from Midori no Hibi.
Although I tried to fight it, I think the professor and Protecto-boy still manage to look like Mario and Megaman. >.>
Made in Flash