In Chapter 11, these two dudes are mentioned as being false prophets. God says to Ezekiel,
"Mortal, these are the men who devise iniquity and who give wicked counsel in this city; they say, The time is not near to build houses; this city is the pot, and we are the meat. Therefore prophesy against them; prophesy, O mortal." (11:2-4)
(They think that being the "meat" in the pot would actually be a good thing, since they'd be protected from outside invaders.)
While Ezekiel prophesies against them, Pelatiah drops dead, struck down by the wrath of God. And that's really all there is to say about these guys.