Threat Dragon is a free, open-source, cross-platform threat modeling application from OWASP. Threat Dragon is open source and contributions to the repo are welcome.
The Threat Dragon logo is called Cupcake, and we aim to make threat modeling less threatening.
The first commit to the original threat dragon repository was made on 9th October 2015, so that is Threat Dragon's birthday. Cupcake has a birthday as well: DЯΣΛMƧVΣЯƧΣ uploaded the original artwork on 7th May 2012.