The Sisiyut‡ is a double-headed serpent and one of the most powerful figures in Kwakwaka'wakw tradition. The Sisiyut‡ has a frightening snake-like body with two serpent heads that extend in opposite directions from the humanoid face in the centre.

A Sisiyut‡ has powerful abilities of transformation and can change into a salmon or even a canoe. To touch or to see the dangerous Sisiyut‡ means certain death. However, for some, particularly warriors, Sisiyut‡ brings supernatural power. A drop of Sisiyut‡ blood can cause a warrior's skin to turn to armour. The skin of a Sisiyut‡ can be used to make a belt that allows the person wearing it to perform superhuman feats. Sisiyut‡ can also be a d‡ugwe' (treasure), or privileges belonging to families, such as the whale, echo, sun for example in the T‡a'sala, which is the second part of the potlatch.

This is a heavy, padded woven cedar bark belt to which are attached (by binding with cords) three woodcarvings that make up the central face and two side heads. The ears on both heads and the body are separate pieces. The eyes, nostrils and ears on the heads and the eyes and ears on the body are inlaid with mirror glass.

The Sisiyut‡ makes his entrance with a club in his hand after striking the door with the weapon. He walks around the fire and goes behind the singers, crying "ai he ik"! The singers begin to use their batons, and behind them a man's head with horns slowly rises far enough to show itself to the people. The two hinged arms representing the body and heads of the double-headed serpent, Sisiyut‡ are at first folded together, extending straight back behind the man's head then they are unfolded and spread out on both sides. A man concealed behind the singers manipulates the apparatus to give Sisiyut‡ motion.

This mask is believed to have originally come from Bond Sound. It was surrendered to the Canadian Museum of Civilization in 1922 and was returned to the U'mista Cultural Centre in 1979.