Chuckya did not originate from fanon, and the information on this page may not be entirely accurate to their canon. You may read more about this subject in the context of their canon on the following wiki(s):
Chuckyas (also spelled Chuck-Yas) are large, purple Bob-omb creatures with red boxing gloves. They appear in Super Mario 64 and its remake Super Mario 64 DS as uncommon enemies. Unlike other Bob-ombs, they do not attack by exploding. Instead, they attack in a similar fashion to King Bob-omb in that they chase Mario to grab him, throwing him around afterwards. The only way to defeat them is to pick them up from behind and throw them, as they will be destroyed upon impact.
Mario Hoops 3-On-3 Deluxe
Chuckya appears in Mario Hoops 3-On-3 Deluxe as a playable character. He is an All-Around character type and his special move is Spin Shot. He is a secret character and to unlock you must beat King Bob-omb in Story Mode on Normal Difficulty (or above). He also appears as the two partners of King Bob-omb in the King Bob-omb Boss battle