From this page of the Valheim guide, you will learn how to obtain Ooze, a useful crafting resource.
Ooze is one of the resources that can be found while exploring the vast world of Valheim. It is used to make Poison arrows and Ooze bombs.
Ooze) is obtained after defeating enemies in the Swamp biome: Bloob, Oozer. Since these creatures are highly poisonous, you might want to take them down using a bow. It is also a good idea to take some Poison resistance mead with you to reduce the damage received from this status effect by 50%.