Shock Canister Harpoons are a type of ammunition in Horizon Forbidden West compatible with only one Ropecaster. While it deals very low Impact damage when attaching to a target, the canister can be set off by Shock arrows, triggering an explosion that deals high Shock damage and very high Shock buildup.
These can be used to inflict the Shocked state on enemies, which temporarily immobilizes them and renders them vulnerable to additional attacks, critical hits, or overrides. Effective against enemies with shock vulnerability.