So, I'm making a game, of course. I'm nearing the completion of this one, and I thought it would be fun to put in some characters from other computer/video games as sort of "cameo" appearances. This obviously led to the question: will I get sued? My guess is a definite yes, and that I can't do this without asking permission (which would be hard/impossible for some of them, since they are ancient, bummer!). Am I correct?

And then either way, I know I've seen cameos in other games, and I've often wondered if those were all explicitly allowed. Is this common?

And then either way, I know I've seen cameos in other games, and I've often wondered if those were all explicitly allowed.

They would've been explicitly licensed, yes.

One of the characters I am interested in is the Dopefish. In case you don't know, it has made cameos in one million games (and that's an exact figure!). Do you think those were all licensed, too? I can't imagine that it is, but I could certainly be wrong.

Moving on, assuming that the above is all true, and without explicitly licensing characters I cannot stick them in a game of mine, I see two options:
a) Just forget about this cameo/reference business.
b) Can I just make a character that looks very similar? My plan all along was to make my own artwork of these characters. It seems unlikely that the look of characters could be copyrighted or whatever, but I'm usually astounded when it comes to the pettiness of intellectual property stuff. And since the names of the characters won't even come up (for instance, a Dopefish could be swimming in some pool in the background somewhere), only the look of the characters comes into question. Thoughts?

Dark, read the FAQ on using other people's IP. Click the FAQ link above. And read this, too.
Nobody can tell you if you WILL get sued, since nobody can foretell the future. But YOU have to decide if you're willing to take the risk.

If there is a risk, it isn't worth it to me. My only question now if whether IP crap applies to a character's appearance. For instance, if I were to make a blue hedgehog, could Sega go and sue me?

if I were to make a blue hedgehog, could Sega go and sue me?

How likely is it that the blue hedgehog would be perceived as being Sonic?
Have you read the FAQ yet? You need to read about this issue.

[quote name='Dark_Oppressor' timestamp='1310893448' post='4836287']
if I were to make a blue hedgehog, could Sega go and sue me?

How likely is it that the blue hedgehog would be perceived as being Sonic?
Have you read the FAQ yet? You need to read about this issue.
[/quote]

I did read the FAQ, and I also read the question on your site. I think I've read most of the stuff on your site already, anyway, haha.

In case I didn't specify, I'm making my own game, and the characters in question would just be cameos or "references" to other games that came before. The whole thing is entirely my own creation. Graphics, music, sound, code, and so on. Obviously, that is not the same thing as making my game and using Mario as the main character. However, I am guessing that legally they are the same thing? That sums up what I was guessing before I asked this, but I wanted to confirm before I just gave up on having fun references in my game.

"If you ever have to ask 'will this get me in trouble,' and you don't want to pay an attorney to find out, you shouldn't do it. Simple. Remember-- Just because you might have a DEFENSE doesn't mean you can't get SUED." - That pretty much summed up my original thinking, but I was hoping someone would tell me I was wrong.

As for your question about the blue hedgehog, my next question is "where is the line, there?" to which I fear the answer is "to be determined in court." Am I correct?

my next question is "where is the line, there?" to which I fear the answer is "to be determined in court." Am I correct?

That's unluckily exactly it. Although common sense tells you that nobody can just trademark or patent "blue hedgehog" or "the letter A" or "multiply two numbers", people have very successfully done just that (the colour magenta has been patented in my country...). Common sense does not apply here and it does not protect you.

Thing is, even if a claim is total bollocks, it is still entirely possible that you have to pay a 5 or 6 figure sum for court fees in the worst case (and if you can't afford that, it's just bad luck).

It gets worse if there is the actual or alleged possibility (due to close resemblance) that whatever you do could be confused with an existing competitive product. Because in that case, in addition to the already painful court fees, you are very likely to lose the lawsuit. If that happens, you can as well spend your last few dollars on a gun. It needs not be a pretty one, you'll only use it once.

All in all, you are never safe from lawsuits (except if you base your company in.... one of those countries, you know...) but the point is, you can ask for a lawsuit or you can not ask for one.

my next question is "where is the line, there?" to which I fear the answer is "to be determined in court." Am I correct?

You've read the FAQs, yet you still have to ask this? You just can't handle the truth! So you're asking, "really? Are you sure?"
You're the king of de Nile!

The whole thing is entirely my own creation. Graphics, music, sound, code, and so on. Obviously, that is not the same thing as making my game and using Mario as the main character. However, I am guessing that legally they are the same thing?

But it isn't all your own creation if it contains characters created by someone else.

With the exception of Fair Use, which doesn't apply in this case, you need a license to use characters that are copyright of someone else. Doesn't matter how you intend to use them, you need a license.

How close can a copy be? Well, if it is close enough to be recognisable it is close enough for someone to take you to court so there really is no meaningful answer to that question.