Beast Gohan is admittedly a bit difficult in this regard because it's a "singular talent," to quote Whis. No one knows about it or expects it to happen, so its appearance is something of a surprise.

Gohan's strength comes from Goku and Piccolo's mentorship, sparking a debate about whose finishing move suits him best. For Gohan, adopting either Goku's Kamehameha or Piccolo's Special Beam ...

Will Gohan Be Number One? During the events of Dragon Ball Super: Super Hero, Gohan was able to achieve his Beast form by unleashing his anger in the face of Cell Max.