Are Bootlegs always visible on the overworld?

[BronzeGoblin]

I only have two bootlegs, an Electric Macabra, and an Astral Jellyton.

I found the Jellyton easily on the overworld, as it was a different color, and flashing a bit. the Macabra, I can't remember.

Are bootlegs always visible from the overworld? Or is there a chance they'll look normal before engaging?

[Donnicton]

If it's a normal overworld enemy then they will be visibly glitchy and alt-colored prior to entering combat, however if it's a rogue enemy(the black shadows) then you will not be able to tell until you enter combat.

The easiest way to tell if an enemy is a bootleg in combat (besides color) is whether or not their name is red, rather than black. If it's a fused enemy and its name is red, then at least one of the two is a bootleg and you need to split them before you can get to it.

[Doca]

Additionally, I BELIEVE that the reinforcement monsters (so the ones that are added to the fight, other than the one that appeared in the overworld) have a chance to be bootleg, BUT if I'm not mistaken these are generated when the battle starts, so you're not "missing" a potential bootleg if you pass on a non-bootleg overworld monster.

[XrayGamerz]

No. Sometimes when you interact with one beast there ends up being two against you. I have seen bootlegs as the second beast that joins the fight that was never initially on the screen. Also Fusion monsters sometimes have a bootleg, sometimes. But a Shiny is a guaranteed bootleg when you see it in the world itself.