Crimson Sentry is a common toad unit that damages and poisons nearby enemy units on death. The damage and area of effect can be increased when leveled up. Crimson Sentry can work well in control and poison decks.
Crimson Sentry's ability to damage and poison many enemies at once can synergize with other cards well.
Crimson Sentry's 2 movement and death damage make it a strong front pusher. If your opponent tries to get rid of it using another unit, they'll be poisoned. However, your opponent can use ranged effects or spells to avoid that.