Transformers: Yokohama Decepticon Secret Base

Through the machinations of Tarantulas, NAVI-ko is "warped" into a body of her own, which transforms into a dolphin. She debuts her new form to the bemused Megatron as she presents him information (secretly provided by Tarantulas) on "Nemesis Prime", an evil clone of their ancestor, Optimus Prime. Megatron wants to add Nemesis Prime to his own forces, so he sends NAVI-ko back in time via a transwarp portal to Doctor Arkeville's Decepticon Base in Yokohama, Japan, in the year 2014 where Nemesis Prime has been detected.

*Note: Tie-in manga released online to promote the 2014 Transformers Expo in Yokohama.

(Source: TFwiki)*