Clag is an Australian brand of glue made by Bostik.
The non-toxic glue is aimed for use by children in schools.
[1] Clag was first trademarked in 1898 by Joseph Angus of Melbourne.
[1] During the 1970's and 1980's Australian punk rock era, Clag glue was used by punk rockers to stiffen their hair in the style of a mohawk.
It would make the mohawk "hair spikes" rock hard and took at least an hour under a shower to soften it enough to be removed.