Scizor's screech turned from pain-filled to pain and rage-filled. It suddenly retaliated by firing a Hyper Beam at Stan. Left with no time to dodge, Stan tried to block it with Hydro Pump, though it was size smaller due to the ongoing Sunny Day. Not that he had much of a choice since Hydro Pump was the only move he could perform at such short notice that stood a chance against Hyper Beam. Still, despite Sunny Day, Stan's Hydro Pump managed to stop it in its tracks, dragging the Hyper Beam into a beam off. Scizor did not like that at all and released an angry screech following which its Hyper Beam suddenly increased by two sizes.
Webnovel 
I imagine Stan does have hyper beam, but because of the timing, the move mastery of hydro pump made it the only choice to defend with.
Scizor's screech turned from pain-filled to pain and rage-filled. It suddenly retaliated by firing a Hyper Beam at Stan. Left with no time to dodge, Stan tried to block it with Hydro Pump, though it was size smaller due to the ongoing Sunny Day. Not that he had much of a choice since Hydro Pump was the only move he could perform at such short notice that stood a chance against Hyper Beam. Still, despite Sunny Day, Stan's Hydro Pump managed to stop it in its tracks, dragging the Hyper Beam into a beam off. Scizor did not like that at all and released an angry screech following which its Hyper Beam suddenly increased by two sizes.
Pokemon Alternate Universe Adventures
Anime & Comics · Azrail93