This card is good in a burn deck if you target an opponent's monster, or if you have a "Prime Material Dragon", then you could target your own monsters and gain life points.
If you have multiple "Mecha Bunnies" in your deck, they combo well with "The Transmigration Prophecy". If you get two "Mecha Bunnies" destroyed and a third is on the field, you could use "Pot of Avarice" and thus get the effect of "Mecha Bunny" five consecutive times. Or, you could simply deal 3000 damage total with 6 "Mecha Bunnies".
This card can effectively counter "Spirit Reaper", since its effect targets one card on the field.
This card does pretty nicely in a Bubbleman Burn Deck since it blocks an opponent's attack, burns them, and mills the deck all at once.
This card has similar effects to "Giant Germ", although it can be considered to be better since it Special Summons in face down Defense Position and doesn't need to get destroyed to deal damage. However, it is vulnerable to "Skill Drain" as its effects activate on the field.