Runo Stromkirk // Krothuss, Lord of the Deep

If the copied creature was copying something else, the token enters the battlefield as whatever that creature was copying.

Although the token is attacking, it was never declared as an attacking creature (for purposes of abilities that trigger whenever a creature attacks, for example, like training).

The token copies exactly what was printed on the original creature and nothing else (unless that permanent is copying something else or is a token; see below). It doesn't copy whether that creature has any counters on it or Auras and/or Equipment attached to it, or any non-copy effects that changed its power, toughness, types, color, and so on. Notably, it doesn't copy any effects that may have turned a noncreature permanent into a creature. If the token isn't a creature as it enters the battlefield, it won't be attacking.