TikToker Mason Hull is fighting back against criminal charges accusing him of buying child porn online, TMZ has learned.

The 18-year-old content creator -- known for his Looksmaxxing content -- entered a not guilty plea to 15 counts of possession of child sexual abuse material.

Mason was arrested on May 5 after detectives said they found videos on his phone of children being sexually abused.

According to the arrest warrant, Mason's girlfriend told cops she discovered the material when she looked through his phone because she believed he was cheating on her.

She claimed to have found messages on the Telegram app where Mason was allegedly paying people for the videos.

During questioning, the docs say Mason told officers he recently wanted to "try something new" and sought out taboo pornography.

He said he spent money twice on buying videos with kids between the ages of 8 and 15. Cops say some of the videos they found showed children crying while being abused.

As part of his release on bond, Mason was ordered not to use the internet, which prosecutors later said he violated. His lawyers told the court Mason was an influencer and said the complete bar on using the internet hindered his ability to earn a living.