The Face... With legs... Is there much more to say? It has 1/2 the stats The Face has, but over 25 times as much speed. Somewhat similar to Shy Boy.
The best way to defeat it is to treat it as if it was a Shy Boy, but without any specific Red/Floating weaknesses. Since it is traitless, Leggsy has less debuffs that can slow its progress. Instead, use plenty of meatshields, and if that isn't enough, weaken it with Thaumaturge Cat. When its running and chomping is put to an end, Leggsy will drop as much cash as an ordinary The Face does, so don't be afraid to use a lot of your budget to kill it.
Time between attacks
170 (area attack)
*In each stage, there is strength magnification, the value of health and attack power varies due to this value.
*Time between attacks is the time of the attack from the motion end until the next attack motion start