When the result of the mutation is Graboid, because of the 'burrow' passive skill it will be spawned underground and assigned a random skill which can be awesome: steal, destroy, growth, or redundant: immaterial. This is just a bonus you may get with Mutation, like other passive skills: poisonous, airborne, etc.
Graboid with Hatch makes for some really unique scenarios. Typically when a mutant gains Hatch, the creature that is subsequently created is also a mutant-so it's the same as if you cast mutation on it.
Because the Graboid is already burrowed, the info box will display the 'invulnerable' status in place of the normal 'mutation' status you would get with any other image. Because it is no longer considered a mutation, if it has the Hatch ability it will then hatch into any creature like a Fate Egg would (standard stats and skills present) and it is still in its burrowed state. This can also be accomplished by Quinting other mutant creatures with Hatch.
If the Graboid hatches into a Deja Vu and you use its skill, the original Deja Vu will remain burrowed, but the copy will not. The copy will have the 1|1 stats, no skill, and the invulnerable status. So, it will be untargetable even though it is not displayed as being burrowed or with the
symbol.
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http://imageplay.net/)