Spider Climb: The arachno-horse can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.   Trampling Charge: If the arachno-horse moves at least 20 feet straight toward a target and then hits it with a bite attack on the same turn, the target must succeed on a DC 14 Strength saving throw or be knocked prone. If the target is prone, the arachno-horse can make another attack with its bite against it as a bonus action.