Octolock

In game description

The user locks the target in and prevents it from fleeing. This move also lowers the target’s Defense and Sp. Def every turn.

Using Octolock in Cobblemon

Octolock deals no damage, so its value is entirely in what it sets up. Status moves are usually the difference in a close gym fight, and sleep or paralysis also make a wild Pokemon far easier to catch.

Check the type chart before relying on it, and look up specific targets in the Pokedex where dual-type multipliers are already worked out.