[darraghenright]

I've spoken English as my native language for almost five decades and I've never seen/heard the word "shranked" before.

This surely cannot be correct. Even the title of the linked article doesn't use "shranked". What?

[forgotpwd16]

Commonly (since ca. 19th century), shrank is used as the past tense of shrink, shrunk as the past particle, and shrunken as an adjective. The title of the linked article uses "shrunk" as past tense and the submitted title was changed to "shrunked" for some reason. "Shranked" was not mentioned anywhere. (But "shrinked" has had some use in the past.)