Michael Lewis -- the man accused of stalking Caitlin Clark -- appeared in court on Tuesday and immediately made waves ... exclaiming he was "guilty as charged" before the proceedings even got started.
The bizarre scene all unfolded inside of an Indiana courtroom ... just two days after Lewis was arrested in Indianapolis on allegations he sent harassing and disturbing messages to Clark throughout December and January.
The 55-year-old Texas native -- wearing an orange jumpsuit and handcuffs -- was escorted into the courtroom by authorities .