We've seen braying donkeys and harrumphing elephants in ads for Georgia's 6th District, muck shovelers and light-saber battlers. And now we have a menacing alligator and a diesel-powered, industrial strength swamp-drainer.

Bob Gray’s 45-second ad, which will begin airing in digital spots Wednesday and on TV next week, opens with Donald Trump’s pledge to “drain the swamp” and a lurking gator. And it ends with Gray, a former Johns Creek councilmember, firing up a water pump to start clearing the sludge.

“I’m running to fuel the economy,” Gray said as he pours gas into the engine, “choke off wasteful spending and secure our nation. But most importantly, I promise to drain the swamp.”

He wades into the murky muck wearing boots and camo-colored coveralls to position the pump. Then, over the roar of the machine, he yells: “I’m Bob Gray, conservative Republican. And I approve this message.”

It continues a rather dirty theme emerging in the race to represent the suburban Atlanta district long held by former Rep. Tom Price.

Former state Sen. Dan Moody launched a $300,000 ad campaign Monday featuring him with a shovel, gloves and a resigned look as he trailed warring donkeys and elephants.

And Democrat Jon Ossoff rushed to defend himself with a trio of nose-to-the-grindstone ads after a GOP super PAC strung together footage of him while at Georgetown University dressed as Han Solo and joking about drinking games.

Gray’s campaign wouldn’t say how much money they were putting behind the ad, though they said it was a “significant” buy.

Gray is one of 11 Republicans – and 18 candidates overall - in the free-for-all April 18 special election to replace Price. All candidates, regardless of party, will be on the ballot. The top two vote-getters will square off in a June 20 primary.

The district spans from east Cobb to north DeKalb and was the launching pad for Newt Gingrich, Johnny Isakson and Price, who is now Trump’s health secretary.

It has been a Republican stronghold for decades, but that hasn't stopped Democrats who hope Donald Trump's election has energized their supporters. Hillary Clinton fell about one point short of winning the district, though Price was re-elected with roughly 62 percent of the vote.

And while bigger names are in the field – the presumptive frontrunner is former secretary of state Karen Handel – recent polls show Gray within striking distance of the top two slots.

More about the Sixth District:

Dan Moody’s ad debut: ‘I’m going to need a bigger shovel’

All about the Georgia 6th congressional district election

The fight over Tom Price's seat could be a referendum on Trump

Ossoff strikes back: Democrat rushes to define himself with trio of ads

Republicans target Jon Ossoff in Georgia’s Sixth with ‘Han Solo’ ad

Karen Handel vows to fight the 'status quo' in 6th District bid

A ‘make Trump furious’ Democrat navigates race for Georgia’s Sixth