Benthic Behemoth

Landwalk is a generic term that appears within an object’s rules text as “[type]walk,” where [type] is usually a land type, but it can also be the card type land plus any combination of land types, card types, and/or supertypes.

Landwalk is an evasion ability.

A creature with landwalk can’t be blocked as long as the defending player controls at least one land with the specified land type (as in “islandwalk”), with the specified type or supertype (as in “artifact landwalk”), without the specified type or supertype (as in “nonbasic landwalk”), or with both the specified type or supertype and the specified subtype (as in “snow swampwalk”). (See rule 509, “Declare Blockers Step.”)

Landwalk abilities don’t “cancel” one another.

Multiple instances of the same kind of landwalk on the same creature are redundant.