This is a model of one of my favorite Mario enemies, Pokey.
Most people don't know what this cutie's name is, they just know him as the tall spiky thingy that you have to kick out all the lower balls until you get to the head to kill ... phew, that's wordy!
Anyway, this neat model is an Icthus7 design that you can find on his blog:[link]
And the base is something that I found while surfing the net ages ago, and I can't for the life of me remember where, so I can't give out the credit, sorry.
But you can download it from here:[link]