Ram "Mystic Tomato" into another monster to kill it while this card is in your grave. Then, in chain, summon this card from the grave and a low-ATK level 5 monster (like another copy of this card, or "Garbage Lord") to Xyz summon the Rank 5 Xyz of your choice.
This card will not be banished as a result of its effect if you use it for an Xyz Summon, and then detach it for the Xyz Monster's effect, because Xyz Materials are never treated "to have left the field". This can be used to gain the same "Interplanetarypurplythorny Beast's" effect multiple times.
Discard this card from your hand to the graveyard to special summon "Dark Grepher".
Have "Interplanetarypurplythorny Dragon" in your hand when "Grepher" is destroyed by battle, then you can activate both Interplanetarypurplythorny effects (Hand and Graveyard) to special summon them both and Summon a rank 5 next turn.