From Kotobukiya's silicone ice cube tray series, it's an Alien egg pod!! These have a temperature range of -40 to 230 degrees Celsius (-40 to 446 degrees Fahrenheit), so you can use them for a variety of things, such as ice, chocolate, candies, gelatin, and mini-cakes (for trays with larger sections).
Each tray measures approximately 11 x 16 cm (4.3 x 6.3 inches), about enough for one glass of ice. Be sure to buy several if you plan on having friends over!!