The Roachoid boss is the third boss in Duke Nukem: Manhattan Project; he's encountered in third part of the third chapter Metro Madness. Like the standard variants he can attack Duke by spewing G.L.O.P.P. at him as well as close combat attacks. He has the appearance of a Level 3 Roachoid and Duke will encounter him before meeting any of the standard Level 3 roachoids.
Just before the boss appears Duke will be on top of a much longer train but when he gets further up the three car's nearest the front will uncouple and leave the rest of the train behind. Duke will encounter him on top of a train that now consists of only three cars, as well as fighting the boss the player needs to make sure they don't fall of the train or they'll be killed instantly. During the fight the player can go inside the train as well as the top of each car. The boss spits out a G.L.O.P.P. blob that can reach the player no matter how far they are from him so the player can't hide and expect him not to hit them as a hit from his G.L.O.P.P attack does 15 damage. In addition even when the player is in the train, they should never hang around too long there because the boss can spit a rather large blob of G.L.O.P.P that drips down the train and then spreads around like electricity on water which can do quite a bit of damage if the player walks in it; as a result of this the boss doesn't really need to move. Like the Level 3 roachoid he curls up after each attack which makes him invulnerable for a couple of seconds, so the player should be careful not to waste ammo when he does this. As long as the player doesn't take too much damage from his attacks they should have no trouble beating him so a good way of doing this is to shoot him and then jump to the otherside of him, shoot him again and repeat the process which will mean he'll have a hard time hitting the player and it's possible to beat him this way without suffering any damage whatsoever. He also can do 30 damage in melee and the damage he does is identical to the standard level 3 variant and aside from his higher health what separates them is his G.L.O.P.P attack is a lot more specialized than the level 3 variant. When Duke defeats him he drops two Nukes.