Poison.
The poison of serpents and of asps is used in scripture symbolically for the judgement of God and for the malignity inherent in the wicked. Deuteronomy 32:24, Deuteronomy 1:32; Job 6:4; Job 20:16; Psalms 58:4; Psalms 140:3; Romans 3:13. The tongue is "an unruly evil, full of deadly poison." James 3:8. Job 6:4 apparently alludes to arrows being poisoned.