The headcrab_canisters_tool.zip file you have requested: Modifications / Garrys Mod / Add Ons / Garrys Mod: headcrab canisters Summoner (V2.0) - 21.11kb is not available. Perhaps try browsing all files for the game Half-Life 2 and upload any files you want to share or are missing. This is the only information we could locate:
For more information on Half-Life 2, visit Halflife2.filefront.com This is the same basic weapon as the first one, but with some good changes. Primary fire still summons a headcrab canister from the sky.