Alright, I made this account literally just for this.
There's this anime from over 10 years ago, I know this for sure because I was 7 when I watched it the first time (18 now)
I have very good memory, which is why i've hold onto remembering about this anime for so long, but never managed to remember the name or find it online, I'll get to the point now -
What I remember most clearly is that in this anime the main character, which I believe was a teenage boy, fights these cyclops (at least he did in the episode I watched) which were immune to all his attacks, until he hit their weak point which was their eye. Once hit in the eye, the cyclops dissolved into particles and then became a card(?) as in, a yugioh-ish card he could hold.
Other info I have which might be incorrect is - The main character and his friend were in a prison(?)
The main character punched a prison wall so hard it made a wide hole(?)
The main character and his friend got into a fight with some citizens during the episode(?)
That's all I got, please PLEASE help me find this gem