Since June, the “world’s most powerful artist” and “innovator of the year,” Ai Weiwei, has been occasionally mentioning his plans to fight back against the Chinese government over the charges of tax evasion they’ve placed on the artist (and was the supposed reason behind his three month detainment). Now he’s made it official. The BBC reports that Weiwei “has decided to challenge the $2.4 million tax bill” the government sent to him. While his mother has reportedly offered up her house as collateral, as fighting the bill will require the artist to put up roughly half the amount before he’s able to fight back, he might not wind up needing his family to go to such drastic measures. As we had recently written, Weiwei had recently received more than $800,000 (and likely more since that posting) from donors eager to help get him out of this most recent scrape. Though at the time of those donation figures being released, there was some speculation over whether or not the artist would be allowed to use those funds, or if the government would crack down and label them illegal. Whatever the case, Weiwei now appears in full push-back mode.