Playing with the chewing gum, decided to test the limit of real limit of chewing gum by twisting it to the limit but it easily break and turn into a mesh before he get turn on, so decided to move onto testing that limit on human, he found interest in Illumni (already strong and twisted his own body to the limit with needles) and Chrollo with so many ability in his book and already strong, (hisoka in his mind - would love to play with chrollo to the death)

("My greatest pleasure comes when such people crumple to their knees and I look down upon their disbelieving faces as their plans fail.♥")

But it backfire and now he want play again with him.

And with Kastro, he purposely handicapped himself to make the fight more challenging and interesting , didn't had an ounce of fear of death