"Rainbow-coloured" does not demonstrate the trope. How about we go for something more strongly indicating invincibility?
EDITED IN: What comes to mind is the Sonic series, given the abundance of obvious threats like lava, spikes, etc... more obviously harmful than goombas or koopas. Give me some time and I'll come up with a good screenshot from one of the earlier Sonic games.
EDITED IN after: Here it is.
edited 25th May '12 4:57:43 PM by HiddenFacedMatt
"The Daily Show has to be right 100% of the time; FOX News only has to be right once." - Jon Stewart
Very tall and unattractive. I say this in general about a Multi Part Picture for this page—a simpler image if any would be acceptable.
As for the "rainbow" thing: I see images of Mario sometimes, and rainbows definitively aren't something I see often there. Plus that the pose looks definitively like a power-up.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman"We leave too many pages imageless as it is."
An imageless page is better than a page with a bad image. Leaving the page blank again is in fact better than all the suggestions, according to the votes thus far.
Becky: Who are you? The Mysterious Stranger: An angel. Huck: What's your name? The Mysterious Stranger: Satan.That said, perhaps the Sonic invincibility powerup could be shown in 2 parts.
"The Daily Show has to be right 100% of the time; FOX News only has to be right once." - Jon Stewart
I don't see a powerup, I just see a computer screen. I don't see a reason for him to not always have the invincibility. I don't think those screenshots are ever going to work as a page image; they're dark and unclear.
Rainbow!Mario strongly implies the trope and has value as an image, so I think that's the best of the options. It's clear (having never played SMB or related games) that he has a powerup, and it can easily be infered that it's invincibility.
That was the amazing part. Things just keep going.Sandbox.Invincibility Power Up RM
edited 27th May '12 2:07:12 PM by rodneyAnonymous
Becky: Who are you? The Mysterious Stranger: An angel. Huck: What's your name? The Mysterious Stranger: Satan.No one would assume that it is. Unless there truly is the type of person who would see that image and go, "So this guy's normal appearance is all rainbowy and sparkly. What does this have to do with the trope?"
edited 26th May '12 4:56:12 PM by FinalStarman
I'm not crazy, I just don't give a darn!... in hindsight, with even that taken into consideration, perhaps it might be better than nothing, if no better options are presented. For now, I say we keep looking.
EDITED IN: Another option, from Super Mario 64.
EDITED IN after: Or alternatively, Super Mario Bros 3.
edited 27th May '12 1:06:49 PM by HiddenFacedMatt
"The Daily Show has to be right 100% of the time; FOX News only has to be right once." - Jon StewartFirst one doesn't work; it doesn't show the powerup per se (just the item box), and Metal Mario's too difficult to spot in the flames.
Last one has some potential though ... world 7, eh? Give me half an hour and I can grab a better shot.
I still want to get one from Mario 3, but here's one from Mario 1, All-Stars version:
edited 27th May '12 2:27:24 PM by Stratadrake
An Ear Worm is like a Rickroll: It is never going to give you up.First one, to me he looks, well, dead.
Second one, he's tiny at first and it took me a while to see him in the second. I'm game for if a better version can be produced, but I'm dubious.
That was the amazing part. Things just keep going.Too big, not focused enough on the trope. I'm gonna say rainbow Mario does the best job of getting the trope across, although he could be a lot better.
"If you aren't him, then you apparently got your brain from the same discount retailer, so..." - Fighteer
Crown Description:
Nominations for replacement images:

Upvoted the rainbow picture - flashy colours sound more like this than the rather pixelated graphics in the other pictures.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman