Eine Wollkrabbe ohne Tarnung (Schwammhut) klettert auf die Bedeckung einer anderen und versucht diese umzuklappen. Die angegriffene Krabbe läßt nach dem Umklappen den Schwamm los, den sich der Angreifer aneignet. Der Schwamm wechselt öfter den Besitzer; Abwehrbewegungen außer Ducken und Drohen kommen nicht vor.

Dromia vulgaris (Dromiidae) holds sponges or Ascidia colonies over its body by means of the specialised two last pairs of the cephalothorax appendages. If an uncamouflaged Dromia detects a camouflaged one, it approaches and climbs onto the cover. The camouflaged animal does not defend by means of chelipeds but only ducks in response to the mounting. The uncamouflaged crab climbs over the sponge towards the posterior, lifts the sponge with one claw and squeezes strongly one of the holding legs with its other claw. The assaulted animal moves forward and leaves the sponge loose, which the attacking crab now puts on its back. The film shows how a case changes owner several times. Intraspecific threat and fighting behaviour with the chelipeds as described for other water-living crabs, has not been observed in Dromia up to now.