According to the Republicans, Colleen Lachowicz enjoys "poisoning and stabbing" on the PC MMORPG, raising doubts about her "fitness for office".
On a website created by the opposition party called 'Colleen's World', information is stated about Lachowicz's World of Warcraft character - a level 85 orc rogue called Santiaga.
The website also highlighted various comments Lachowicz has made in the past on the internet.
One such post read: "I love poisoning and stabbing! It is fun. I never thought I would love it so much either. I did not start out in WoW with a rogue."
Maine Republican Party spokesman David Sorensen stated: "These are some very bizarre and offensive comments.
"They certainly raise questions about Lachowicz's maturity and her ability to make serious decisions for the people of Senate District 25."
Lachowicz responded on her website: "I think it's weird that I'm being targeted for playing online games. Apparently I'm in good company since there are 183 million other Americans who also enjoy online games.
"What's next? Will I be ostracized for playing Angry Birds or Words with Friends? If so, guilty as charged!"
The state senate seat, known as District 25 in Maine, is currently being contested by Lachowicz and Republican Tom Martin. Voting takes place on November 6.
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