Sand hopper

Playa Tamarit, Santa Pola, España (2012)
One likely prey of the previous spider since they were found in the same place. It is a common amphipod crustacean of sandy coasts around Europe. The typical "hopping" movement gives the animal its common name, and is produced by a flexion of the abdomen. In order to do this, it must stand on its legs (amphipods usually rest on their sides) and suddenly extend its abdomen out from under its body. It can leap several inches into the air.
Habitat:

It is found around the coasts of the North Sea and north-east Atlantic Ocean from southern Norway to the Mediterranean Sea. In most of its range, its daily cycle is strongly linked to the tides, with daily migrations of up to 100 m (328 ft), but where there are no significant tides (as in parts of the Mediterranean), visual cues are used instead. Talitrus saltator spends the day buried at depths of 10–30 cm above the strandline, but emerges at night on the falling tide to feed. Their diet is composed chiefly of the rotting seaweed which accumulates on the strandline. T. saltator is an important food source for shore birds.