The tractor-web was a chemical sealant that formed into blue webbing. It was adapted from Tholian equipment in the 23rd century.
History[]
In 2267, a Grotus transport fled from the Federation wildlife preserve planet Salvum. To prevent the USS Enterprise from pursuing them, the vessel fired on the planet’s atmospheric shield, creating a hole through which the planet’s controlled atmosphere immediately began to dissipate. All life would be killed on the surface within hours unless the hole could be patched. Thinking on his feet, Montgomery Scott asked James T. Kirk if a device he’d captured recently from a Tholian vessel was still on onboard. It was, and Scott removed chemicals from the device, adding them to modified loading charges of four phaser rifles. He and three engineers in gravity control suits piloted Galileo to the damaged area of the shield, then exited the shuttlecraft. Using the phaser rifles, they sprayed the chemical sealant, forming a criss-crossed web pattern to plug the fissure. Scott felt that the seal would hold until a permanent repair could be made by a repair crew. (TOS comic: "Sport of Knaves")