An environmentally themed Portland mayoral debate on Wednesday night saw two foiled gatecrashing attempts by lesser-known candidates on the ballot.

The most surprising incident of the night came when moderator April Baer called the candidates onto the Benson High School auditorium stage, where a podium each was set aside for the three leading candidates: Eileen Brady, Charlie Hales and Jefferson Smith.

As Brady, Hales and Smith filed onstage, but they were followed by environmental activist, arsonist, pragmatic defendant and most recently domestic violence arrestee Tre Arrow.

Arrow is also running for mayor, but, along with 19 other long-shot and vanity candidates, was not invited.

Oregon Public Broadcasting's Baer at first failed to notice Arrow, who was standing next to her as if waiting for a turn at the microphone. When she refused to relinquish it, he strode forward on the stage and addressed the audience.

Arrow criticized the moderators for inviting only "the three richest candidates," then appealed directly to the audience. He said if audience members wanted him to speak, he would.

"If you folks say, 'No Tre, take a seat—'" Arrow went on, but he was cut off by a man in the rear of the auditorium:

"Take a seat!" the man shouted.

Then the rest of the room joined in, shouting for Arrow to return to his seat. Arrow shrugged and went back into the audience, chastened.

Earlier in the evening, a member of the event staff confiscated a bullhorn from 21-year-old Cameron Whitten, a thrice-arrested Occupy Portland demonstrator who is also running for mayor, as he moved through the crowd shaking hands. Whitten relinquished the bullhorn with little complaint.

The April 18 candidate forum was hosted by the Oregon League of Conservation Voters, the Sierra Club and Oregon Environmental Council.