Where can I read more about the rare special supernatural creatures mentioned in Buddhism? There are some special supernatural creatures mentioned in the Buddhist Tipitaka, which include for example:


Beings of negative births living like gods
Floating creatures in immense pain only seen by the Arahants
Evil creatures who only reside in ponds in the jungle
Evil creatures who eat their own babies


Where in the Theravada Tipitaka can I find out more about these creatures? These stories are ascribed to (i.e. told by) the Buddha.
I think you're looking for or trying to reference the "Petavatthu" in the Khuddaka Nikaya.

Wikipedia says,


  The Petavatthu is a Theravada Buddhist scripture, included in the Khuddaka Nikaya of the Pali Canon's Sutta Pitaka. It is composed of 51 verse narratives describing specifically how the effects of bad acts can lead to rebirth into the unhappy world of petas (ghosts) in the doctrine of karma. It gives prominence to the doctrine that giving alms to monks may benefit the ghosts of one's relatives (see Ancestor worship).


A Google search for Petavatthu returns other references and sources and translations on this subject.

Beware that S. Dhammika writes,


  Interestingly, the Buddha considered ‘talk about ghosts’ (petakatha) to be unedifying and unbecoming for serious Dhamma practitioners (D.I,8). The Petavatthu would by any interpretation qualify as ‘talk about ghosts.’ It is also interesting to note that the Thai Sangha has never recognized either the Petavatthu or the Vimanavatthu as canonical. All scholars who have examined the Petavatthu – Rhys Davids, H. S. Gehman and Prof. Abhayanayaka – ascribe to it a late date. Winternitz wrote that it ‘probably belongs to the latest stratum of literature assembled in the Pali Canon.’


He also says that that doctrine was an existing Brahminical belief.

There seems to be English-language translations of (at least 20 of) the stories here: http://tipitaka.wikia.com/wiki/Petavatthu inluding at least one about a creature which eats it's own babies.