The Zombie Blue itself is more valued as a card summoned from Necromancer and Undead Army. The card itself is not nearly as valuable, due to its slow attack however it's the cheapest 1 Gold card for its total Health, even the Nested Blue (90 total Health vs 100).
Like all Zombie Bloons, beware if popping an Undead with Revive property if it's at 0 delay, as it can revert to standard health after popping.
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