Alien trapped on earth

I'm an alien trapped on earth
The color of my skin not of earth
The world saw me but didn't notice
They made me dress just like everyone else

They pushed me to a corner
And demand that I conform
They'll paint my red skin grey
If it's the last thing they'll do

With each step they take forward
I'll take one step backward
I do not wish to see a tragic end
Yet, there's no end to this

Soon, I'll reach the walls
A border they thought had no escape
When that day comes
That wall and all else will exist no longer

For I will detonate it
With a weapon I've brought
From a world far away
But that's the last thing I'd do

Now, with each step they take forward
I'll take one step backward
I do not wish to see a tragic end
There's no end to this