Loggo is a toilet, first found in the bathroom of Mad Monster Mansion in Banjo-Kazooie. He will offer to flush Banjo as a Pumpkin down to the septic tank, to retrieve a jiggy. Also, the Green Mystery Egg for Stop N' Swop, can be found on top of Loggo once the cheat is activated.
In Banjo-Tooie, Loggo is moved to Grunty Industries, where he complains about a clog. You must perform the Bill Drill ability on Loggo to get the Cheato Page which is plugging his pipes.