Adventure Effects are special time-limited buffs available only from certain legendary Pokémon in Pokémon Go, typically unlocked by activating a specific Pokémon form and/or having it learn a particular charged move, usually at a cost of Stardust and candy. Because they are tied to rare event-exclusive legendaries, such as those introduced during Go Fest, these effects remain relatively hard to obtain, and only one can be active at any given time, though players can spend extra resources to extend an effect's duration.

The effects cover a range of perks, including boosted damage or shield-breaking in Mega Raids, easier catching or longer-range encounters, paused item timers, and bonuses to Max Moves. Examples include Mewtwo's Dynamic Punch+ and Future Sight+, Origin Forme Dialga's Roar of Time, Origin Forme Palkia's Spacial Rend, Kyurem's Ice Burn and Freeze Shock (when fused with Reshiram or Zekrom respectively), Necrozma's Sunsteel Strike and Moongeist Beam, Zacian's Behemoth Blade, Zamazenta's Behemoth Bash, and Eternatus's Dynamax Cannon, each lasting between six and twelve minutes.