What is it called when someone uses your name to describe an act?
I'm not aware of a word or phrase that precisely describes this device. It would be quite fun if there is one!
In any case, it is one example of employing a metaphor.
: a word or phrase for one thing that is used to refer to another thing in order to show or suggest that they are similar
: an object, activity, or idea that is used as a symbol of something else
http://www.merriam-webster.com/dictionary/metaphor
Call it "eponymous," describing the giving of someone's name to something. Originally, the adjective described the person who's name is used, but it is now used to also describe the thing so named. Go here.
Eponym: a word based on or derived from a person's name
Eg: Bob's your uncle
It sounds like a specific form of personification, one definition being
Artistic representation of an abstract quality or idea as a person.
American Heritage Dictionary
The term incarnation also might apply
a person or thing that typifies or represents some quality, idea, etc ⇒ the weasel is the incarnation of ferocity
Collins
Maybe something like:
- count nounification of a name
- name metonymy
- eponymic metonymy
- or, as a previous poster suggested, eponymous or eponymic metaphor
The problem with eponym simpliciter is, in my opinion, that it connotes the use has been lexicalized or standardized to some extent.
Interestingly enough, in contemporary philosophy of language and syntax, such examples as you gave involving the use of a name as a count noun rather than a proper noun have led many syntacticians to postulate that names are marked in the mental lexicon as count nouns and that when they occur in positions apparently lacking determiners or other modifiers (i.e. their usual positions), such elements are actually there covertly. I am thinking of the work of Ora Matushansky and Delia Fara.