A generic archetype for an anecdotal old person or animal; usually derogatory when used towards an old man ie, geezer, but can be used as a term of endearment for pets that resemble an old man .
"Just remember to pay ol' Man Mcgee his dues!" (using terse air quotes around Ol' man McGee, insinuating that this person is old, crotchety and greedy)
"Oh look at that old man dog, he's so cute! Look at me, I'm ol' man Mcgee!" (said while playing with the dog using affectionate dog speech)
"Hey kids, I'm ol' man McGee, stay off my lawn or I'll cane ya!" (said in an Adam Sandler comedic pitch)