Advanced format ruling
Cloudian - Acid Cloud
Card effect (current official text)This card cannot be destroyed by battle. If this card is in face-up Defense Position, destroy it. When you Normal Summon this card, place 1 Fog Counter on it for each "Cloudian" monster on the field. You can remove 2 Fog Counters from this card to destroy 1 Spell or Trap Card.
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.