Magus the Purifier said:Just get some Devastation Centipede poison on a arrow.
Fort save (DC 93) Initial and secondary damage 2d12 temporary dex.
It might be expensive as hell and god forbid you cut yourself but it would be impressive to watch a dragon go help less in 1 hit. If you could even get access to such poison.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.