Treborn is a follower pet that could be unlocked between 8 and 22 January 2017. It was made available one day before the planned release of the Memorial to Guthix.
It was unlocked by talking about recalling memories or using the right-click 'redeem code' option with either Diango or Ianto, and entering the code
- 4-8-8-4-4-9 on a standard telephone keypad spells G-U-T-H-I-X. Additionally, 0800 is the standard UK prefix for free to call telephone numbers.
- Treborn may be a reference to the 2004 film The Butterfly Effect, whose main character is named Evan Treborn.
- Initially it was not possible to claim the pet with the 'redeem code' right-click option, this was later hotfixed on 9 January 2017 before the release of the day's update.