One species' discarded childhood toy is another species' treasure: a hermit crab on the beach in Puerto Rico has moved into a large Lego piece.

It’s an innovative solution to a perpetual problem for the crustacean. Hermit crabs can’t grow their own shells, and they rely on snails going belly up so they can steal their homes. (Unless humans steal them first.) And as hermit crabs grow, they are under constant pressure to find a new home that’s more spacious—but not too spacious—and hopefully not too brittle.

To deal with the low-vacancy situation, hermit crabs have been spotted cooperating to shell-swap by size, and, in a pinch, shacking up in bottle caps. Some humans are stepping in to make sure that crabs have well-to-do living arrangements. “They’re sticking their butts into bottles, they’re sticking their butts into shotgun shells, and that’s just not pretty,” Makerbot CEO Bre Pettis joked to Public Radio International program Living On Earth. Pettis explains that he created 3-D printed hermit crab shells for his “crabitat” in Brooklyn.

Other fancy solutions include carefully designed skyline-shaped homes and this glass shell:

Whether the orange-lego residing hermit crab was the victim of a housing crisis isn’t clear, The Dodo reports. Maybe it just wanted to sport a fashionable pop of color for spring.

(H/t Earth Touch)