This Nritya Ganesha (dancing Ganesha) is one of the 32 forms of Ganesha.
Four-armed and balancing on his left leg, this happy Ganesha brings a smile to our faces.
The Vigraha is worn and his lower left arm is broken to identify the attributes. As per the Dhyana Sloka, this Ganesha may hold the broken tusk, elephant goad, Parasu, noose, Modaka (rice dumpling) and fruit.
This Vigraha is only about 6 cm in height and the artist has created magic. The trunk, though appears to be cast as part of his belly, stands on its own. See the waist belt looping below his ample belly. The gap, between the belly and the waist belt, is noticeable when you enlarge the picture above and also on the third photo below.
The Vigraha is from Tamil Nadu and it may be dated to the sixteenth century.