DES MOINES, Iowa — Donald Trump skipped Thursday's GOP presidential debate Thursday night in favor of his own rally in Iowa, prompting rival Ted Cruz to troll the candidate on Snapchat, a popular photo sharing app. It's only the latest effort by the Texas senator to mock Trump's decision before the Iowa caucuses next week.

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On Snapchat, you can add location-based filters to your photos (called geofilters), and Cruz's campaign apparently paid for a sponsored geofilter that takes aim at the presidential debate absentee. If you snap a photo in downtown Des Moines, or at Drake University, the location of Trump's rally, you'll have the option to add a cartoon duckling with Trump-like hair to your selfie.

I happen to be at Drake University at the moment, so here's an example

/Kyle Jaeger 

"Where is Donald Duckling?" the text of the filter reads.

Trump has insisted that he decided not to attend the GOP debate on Thursday over a series of conflicts with Fox News — he thinks they've been unfair to him, especially host Megyn Kelly, who is moderating the debate. But Cruz has put his own spin on the story: He's criticized Trump for failing Iowa voters by missing the event and questioned his courage, arguing that the Republican front-runner is "afraid" of Kelly. 

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"Iowans and Americans deserve to hear from all the candidates," Cruz national press secretary Catherine Frazier said in a statement. "To refuse to answer simple questions about record and policy is a disservice to voters. If you want a job you have to show up for the interview. Trump should be at this debate and his refusal to reflects that his campaign is about himself and not the American people."