Wikipedia
Ludobot
A ludobot is a type of artificial human companion: an entertainment robot, from Latin ludo (play) and bot (robot).
Examples are battlebots, Sony Aibo, Tiger Toys GoGo My So Real Walking Pup and so on.
Simpler is a digital pet, a virtual pet simulated by a computer. Examples are Neopets, Tamagotchis, or Digipets.