Every so often, McDonald's Australia stores issue "filler toys" when the current promotional toy has sold out,
or to use in between promotions.

The set of Space Invasion filler toys was used in 2003 consisting of four hollow 'planets' each containing a  plush 'alien' measuring approximately 10cms tall:

Rocko with Rock Planet
Meltoid with Lava Planet
Orbit with Satellite Planet
Nimbus with Cloud Planet