Rampage is a character from Fallout Equestria: Project Horizons.

She's one of the characters which is more difficult to explain. Essentially she is a pre war healing talisman modified to be fused with a pony's soul to make it indestructible and so able to perpetually regenerate the user making them immortal. It failed, repeatedly but kept absorbing the souls of the ponies it was implanted into, until at some unknown point it started working as intended but preserves a mixture of all of the souls it contains. Two of those were Twist and a zebra, amongst many others. If completely vapourised the talisman will regenerate Rampage as a filly who grows to adulthood in a matter of days.