Virulent

[Becky]

Extremely poisonous or venomous; very active in doing
injury.

[Sarah]

(of a disease or poison) extremely severe or harmful in its effects.

[Marquetta]

very fast [growing]; [spreads] [quick]; like a diease

[Dave Paprocki]

[Bitterly] hostile or [antagonistic]; hateful: [virulent] criticism. See Synonyms at poisonous.
Intensely irritating, obnoxious, or harsh.

[Tariq Zaki]

[Dave] [Mcdaddy]’s [special brew]