The Brazilian pygmy gecko is mind-bogglingly small. As this clip from the recent BBC documentary Life illustrates, it is so minuscule that it is effectively watertight and can rest effortlessly on the surface of the water. It still amazes me that vertebrates can be that tiny.
LIFE will air starting Sunday night on the Discovery Channel (though, as it is narrated by Oprah in the US, I suggest you pick up the David Attenborough-narrated version on DVD instead).