Monster mash upr joining the ghouls of monster high are the new class of hybrids the creepy cool children of two completely different but completely clawesome creaturesr these monster mash ups mean new freaky flaws new dual personalities and spooktacular styler hybrid sirena von boo is part boo tiful ghost part magnificent mermaid and all about going with the flowr a bit of a dreamer she would rather go where the tide drifts her but shersquoll be maneuvering the howlways of monster hi