Term for misspelling used as pun of another word

A portmanteau combines parts of two different words (in this case, "bike" and "-kery", from "bakery") to form a new word.

Wikipedia has a long list, including such words as "cyborg" ("cyb-ernetic" + "org-anism"), "gaydar" ("gay" + "ra-dar"), and "mockumentary" ("mock" + "do-cumentary").

Some portmanteaus—like those above—become regular words in the language, and can assume either less-formal status ("gaydar"), or completely formal status ("cyborg"); the only distinction is where and how people decide to use them.

So in this case, you've simply noticed an informal portmanteau that "didn't stick."

You could also call it one type of a "linguistic blend" in formal speech, but that would be less specific relative to this example. Essentially, that's what the "pun" of your title indicates.