Building • Cost: 3 • HP: 4
Arrives: Put a -1/-1 rune on all of an opponent's units.
②, ⤵ → For any number of cards with runes, add another rune of a kind already there.
Black • Disease Tech II
If a given card has two kinds of runes, Plague Lab can still only add one rune to that card. You choose which kind of rune to add from among the kinds of runes it already has. — Sirlin, 03/02/16
You do not have to add any runes to any cards you don't want to add runes to. — Sirlin, 03/02/16