Tuesday is a very important day for Ted Cruz, but it's been a rough road for the GOP's second-place candidate.

Indiana holds its primary Tuesday, one that Cruz has staked a great deal on. It's 57 delegates is second only to California in states still left to vote, and Cruz has invested a lot of time and money in the Hoosier State as the odds of catching Trump before the convention get smaller with each week.

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Unfortunately the Texas senator is making waves for all the wrong reasons. It's hard enough being called "Lucifer" by a former party leader, but now Cruz is spending time addressing conspiracy theories that have become memes and, in doing so, he's undercutting the seriousness of his campaign (whatever seriousness the 2016 campaign has left, anyway).

But if you haven't been following along, maybe you're a bit confused, so here's a quick overview of some of the bigger conspiracy theories about Ted Cruz.

Ted Cruz is the Zodiac Killer

Ah, the mother of all 2016 election internet memes. And, yet, its origins are actually from 2013.

In case you didn't know who the Zodiac Killer is, he's a man suspected of killing at least five people in the San Francisco area in the late 1960's, one who also sent letters to area newspapers about the crimes and never got caught. They even made a well-known movie about it. It's good!

So how did Ted Cruz get dragged into this and why is it a big deal? The Daily Dot claims the origins come from this tweet in 2013.

#CPAC Alert: Ted Cruz is speaking!! His speech is titled: 'This Is The Zodiac Speaking' — Red Pill America (@RedPillAmerica) March 14, 2013

At some point, the joke cropped up again on social media early in this election cycle, and — as things are prone to do on social media — exploded.

Ted Cruz was born in CALGARY. The Zodiac Killer's first two victims were named CAL and GARY. #ZodiacTed — zeppo wilbury (@ZeppoWilbury) January 20, 2016

Ted

Everyone

Demands

Confirmation

R

U

Zodiac — ceeks (@70Ceeks) February 21, 2016

OK, funny, ha ha, etc. But why does this matter now, after it's been refuted by research? Well, the joke got new life thanks to Saturday's much-talked-about White House Correspondents' Dinner speech from Larry Wilmore. During the speech, Wilmore went on a run of Cruz/Zodiac Killer jokes.

All of this led to a surreal moment on the campaign trail on Monday, the eve of the Indiana primaries, when Ted's wife Heidi apparently felt compelled to not only acknowledge the Internet joke but offer what she thought was a rebuke of the rumor.

Heidi Cruz: My husband is not the Zodiac Killer https://t.co/kDcuM8MNRS — Hunter Walker (@hunterw) May 2, 2016

But, in a twist only the 2016 campaign could provide, she didn't really offer a clear denial and left the door open, saying, “Well, I’ve been married to him for 15 years, and I know pretty well who he is, so it doesn’t bother me at all. There’s a lot of garbage out there."

And, so, the meme lives to fill your Twitter timeline for another day.

@tedcruz you forgot to put "zodiac killer" in your bio — :) (@uhmmelizabeth) April 24, 2016

Ted Cruz's father killed JFK

The newest entry in the Cruz Conspiracy Pantheon, this one comes courtesy of — who else? — Donald Trump. During an appearance on Fox News Tuesday morning, Trump suggested that Ted Cruz's father, Rafael, was spotted in cahoots with Kennedy's assassin Lee Harvey Oswald just days before the shooting.

Problem is, Trump's apparent source on the story is the National Enquirer.

The 2016 GOP campaign just got even weirder... pic.twitter.com/NrLzA4Bklu — Matthew Salter (@MSalt69) April 24, 2016

The tabloid previously accused Cruz of being involved in many extra-marital affairs. And, in light of that, it's worth noting that Enquirer leadership has close ties to Trump.

Still, the conspiracy theory has caught on, and Cruz on Tuesday felt compelled to address it, if even in a sarcastic, exasperated manner.

Yesterday, "Zodiac Killer" was trending. Today, "Lee Harvey Oswald" is trending. Both instances stemming from Ted Cruz stories. — Ryan Parker (@TheRyanParker) May 3, 2016

WATCH: @Tedcruz: "Yes, my dad killed JFK, he is secretly Elvis, and Jimmy Hoffa is buried in his backyard" https://t.co/8u2syfE8CJ — ABC News Politics (@ABCPolitics) May 3, 2016

Ted Cruz is Canadian

Ah, ground zero for Cruz conspiracies. Believe it or not, Cruz is not the first presidential campaign figure to face the Canadian conspiracy. That distinction goes to Chester A. Arthur, the 21st president of the United States. Hopefully, Ted can find some comfort in that.

As for Cruz himself, this one has been around a while but has gotten new life thanks to Donald Trump, who has made the issue of Cruz's birth a talking point (not a shock, given he did the same thing of President Obama previously).

Wake Up America! See article: "Israeli Science: Obama Birth Certificate is a Fake" http://t.co/f7esUdSz — Donald J. Trump (@realDonaldTrump) September 13, 2012

A sampling of Donald Trump's "Canada Conspiracy" tweets about Ted Cruz Image: Twitter

Even Obama got in on the action during his portion of the White House Correspondents' Dinner.

Obama pokes fun at Ted Cruz's "basketball ring" comments from earlier this week. What's next? "Baseball sticks?" https://t.co/hkDIF5Gkrl — MSNBC (@MSNBC) May 1, 2016

Now, this issue is, for the most part, settled. Judges in states like Utah, Pennsylvania and Illinois have already dismissed lawsuits challenging Cruz's citizenship status, declaring him a legal citizen eligible to be on the ballot.

Not that that's stopped the attacks from Trump supporters.

Cruz says America should ask one question. Man interjects: "Are you Canadian?" Man Cruz is debating repeats it. pic.twitter.com/XznoNg5TyX — Sean Sullivan (@WaPoSean) May 2, 2016

And, so, as Indiana heads to the polls, here's hoping that someone uses an exit poll to find out what, if any, of these theories voters believe, and maybe we'll get a little bit of closure.

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