Burrow
Quick Facts:
Burrow is an ability that, for a quanta cost, render the creature invulnerable but halve its attack power.
Burrowed creatures (signaled by a brown circle on the card) cannot be targeted by direct spells and abilities. However, they are still vulnerable to effects of shields such as Ice Shield (Freeze), Fire Shield (Damage), Thorn Carapace (Poison), Procrastination (Time Delay), etc.
The creature’s attack power is halved, rounded down, when burrowing. Unburrowing doubles the attack power.
For example, if a shrieker with 11 attack power burrows, its attack is lowered to 5, since 11/2 rounds down to 5. When it unburrows, though, its attack becomes 10. It does not return to 11.
Keep in mind that burrowing creatures with negative attack power (due to Antimatter) still rounds down (i.e. more negative). For example, if a shrieker with -11 attack power burrows, its attack becomes -6, and unburrowing it will make its attack power -12!
Attack boosts from indirect source are not halved. For example, a Pest with 2 attack boost from Eclipse does not get its attack halved to 1 when it burrows.
Note that Graboid / Elite Graboid enters the game burrowed and cannot unburrow.
