Square

You clicked the square... g̶̗͚͌̇͌͊͝ǫ̵̦́͂͐̕͠o̶̢̼̫͍̐ḍ̶̺̖̮͛͘͠ ̴͈͂l̶̡̞̤̥̺̋u̷̞̩̩͋̇̑c̵͚̪̞͔͐̊̈̈́k̷͔͙͍̼̖̐̏ ̵̝̒̈́͋͝w̷̨̼͕͖̉ḭ̵̢̓̀͊̔͝t̷̥̑̀͑͠h̴̼̲͚͑̐͋̐̚͜ ̶͈̩͙̐͊̚y̸͙͚͕̱̆͜ơ̵̹̝̇̈̕ṷ̶̡̱͛̓̎ͅr̸̡̓͊͊̏ ̸̲̦̉n̵̗̙̽ͅi̴̙̻̽̈́̌̚͜ġ̴̳̙̦͎̤͐̈́̾͘h̴͓̜͈͎̱̀͒́t̶͍̲̀m̵̭͈̥͉͂̅̓͂͜͠a̶̗͛̉ͅͅr̷̼̫̞̐̄̿̆̿e̸̼̐̒͋̂͜

Manually click the square 100 times.

For those dedicated enough to achieve this secret, Do a sequence of keys that's made from 1985 by the notorious company who added a cheat code to Gradius.

Manually click the square 1000 times.

Manually click the square 10000 times.

Manually click the square 100000 times.