Make the edges of the cross appear to be scar tissue and the cross section of your muscles and rib bones.  On the inside could be a schematic of a computer circuit like this:

I like the flames/demons idea. It all depends on what your going for exactly. You could fill it with stars, planets, including the earth to represent what we know is real. You could put some sort of latin inside like..."Veritas vincit" - Truth conquers
"Veritas vos liberabit" - The truth will set you free, with flames in the background. Your options are limitless. Google your heart out.
 

Welcome to the forum...I'm a newb too.

I never said my tattoos were good, his is just particularly bad. 

What makes his "bad" ?

Justice/equality Truth and life

It just looks silly, angry, and regrettable.  It's like when the lead singer of Deicide branded an inverted cross into his forehead.  Sure, at the time he planned on committing suicide at age 33, but he's in his 40s now and has garnered mild financial success, so he probably regrets it to a certain extent. 

Yes, I realize that.  My point is, the tattoo is going to be lame no matter how he finishes it. 

I don;t know if you are famaliar with the anime series Trigun bu there is a presut character who carries a huge as cross from town to town.  When shit happens, the cross, much like the guitar case in Desperado, is revealed to be a small arsenol of weapons as well as a huge as gun itself.  Perhaps you could fill in the empty space with a bunch of pistols, sawed-offs, and then try to mak it clear that the cross is a gun itself.

Yes, I know it's art.  Was that ever a question?  For that matter, how can science be silly, angry, or regrettable? 

The fact that I was making an aesthetic judgment presupposes that my opinion is subjective.  I never said that it wasn't. 

And as for my bias, sure, it always plays a part in my opinions.  No observation, statement, claim, etc. is made without bias.  However, I know a bad tattoo when I see one--regardless of my religion.  But the bottom line is, it's his body, and if he thinks the tattoo is cool then that's fine. 

  Okay I accept that you know a bad tattoo when you see one, would you care to elaborate as to what exactly makes it a "bad" tattoo in your opinion ?   It's not a trick question or anything, honest.

  Thank you.  At last you gave a specific critique and put it in concrete terms.  That helps.   I was simply curious as to what fueled your negative impression of Godless5150's tattoo.

 Do you care to reveal what your own tattoo's are ?  They couldn't be that bad, could they ?

Haha - wow, a nihilistic theist. I'll try to contain my surprise.

you could fill it with a DNA strain (sp? I am 5 guinness in and a few shots of tequila here), or the milky way if you like, I would go scientific wise, but that's me....and I am drunk tonight, could do that demon thing, but I figure people would peg u for a satanist (unless of course you are then go for it)

Theism is inherently nihilistic, yes. 

But we're not talking about God--we're talking about bad tattoos. 

Haha - thanks for taking my obvious being an asshole well. I appreciate it.

You think it's bad? What about the window-to-hell idea? I thought that would be fun. Of course, it's still St. Peter's cross, so maybe something involving the pope?

Now just get it to fill up the inside I think that would look great and make people ponder about it, like science upheavals religion or something like that.

How about inside the upside down cross placing an image of an angry looking Sponge Bob Square Pants holding a can of gasoline in one hand  and a Bible in the other ?  ....too cerebral ?

Problem with the DNA pic is that, even with the best tattoo artist doing the job (and good ones are hard to find), it's going to end up like an elongated crown of thorns logo. See the pic above in the thread if you don't believe me.

If you ever visit the Philippines (or certain parts of Miami for that matter) you then run the real risk of being hailed as a stigmatic freak wonder boy, grabbed by the locals, and paraded upside down with great reverence around the streets every easter, probably before being nailed to a plank of wood.

I recommend a skin graft. Or accepting a life of expensive liquid paper application.

Looks too much like that pic of a type of lectin molecule that eeevery once in awhile, assumes a cross-shaped conformation. Christians love parading that pic around because it shows proof of God in cellular proteins, or something silly like that.

Scratch the upside down cross, get it removed, and replace it with a far side cartoon, or anything, anything other than your average generic angry young man tattoo

I agree completely. "Mom" is always a good bet, unless you go to Mongolia, where it means rape.

That's the problem with tattoos. They were designed to capture their wearer for all time within the strict cultural parameters of a tribe. And they still do.