Former Democratic presidential candidate Bernie Sanders is taking on the Koch brothers this Halloween.

Charles Koch, who with his brother David are known for their millions of dollars in donations to conservative politicians, tweeted a picture of himself in a Darth Vader costume from the "Star Wars" movie franchise.

When you’re the only one in the office in a costume this morning. #HappyHalloween pic.twitter.com/vJLQ28xizk — Koch Industries (@Koch_Industries) October 31, 2016



"When you're the only one in the office in a costume this morning. #HappyHalloween," the tweet stated.

The Vermont senator shot back, ".@Koch_Industries Our great nation can no longer be hijacked by right-wing billionaires like the Koch brothers."

.@Koch_Industries Our great nation can no longer be hijacked by right-wing billionaires like the Koch brothers. pic.twitter.com/svvNE1gdJE — Bernie Sanders (@BernieSanders) October 31, 2016



Sanders' campaign message focused on lambasting the industrialist brothers for their donations to Republican-affiliated super PACs.