For a few seconds, Legolas felt regret.
'Why didn't I use the Special Developer Package on this guy?'
'He would have made much better use of the package'.
'He is almost a perfect beast'.
Throughout the battle against the Warpsnare, all that Legolas was engaged in was observation. He carefully observed the abilities of the Warpsnare to determine if it was worth it for him to take as his 4th contracted beast.
The first Frog form of the Warpsnare was powerful but if that was all that it could offer, to Legolas, taking it was not worth it.
After the death of it's first form though, the ability of the Warpsnare to revive in another form was the first ability that fascinated him.
Knowing that the Warpsnare had a Blood Vampire form increased his overall grade for it. The power shown by the Blood Vampire impressed him, this was the reason why he decided to finally end the show once and for all.