Druid in wild shape: the hit dice are his or those of the beast?

@alessandro_d_tdruid in wild shape:the hit dice are his or those of the beast?On a attack roll druid’s prof?magic obj can be used in w.s?what? use beast HD. use higher of two prof bonuses. can't use magic items unless they specify otherwise.

— Mike Mearls (@mikemearls) February 17, 2016