Terrible Idea No. Whatever
This has no basis in canon, but:
The Animorphs find out about an actual superhero in The Big Urban Area Near Their Hometown. The superhero is called Bad Dog, and they are absolutely terrifying, but they never hurt anybody. They just scare the crap out of bad guys so badly that when the cops arrive, the bad guys are a gibbering mess, or sometimes the bad guys run to the police for help and turn themselves in.
Every time the police try to catch Bad Dog, like, say, by chasing Bad Dog down an alleyway, the vigilante just vanishes into thin air.
Turns out it’s just Erek tricking and scaring the bad guys with cleverly used holograms and forcefields.