Ratman is hiding in the sewer with his loyal rats and stinging flies. To defeat him, you have to get past the rats and dump sludge on Ratman. Once you have scared the flies from him, you can knock him out and handcuff him.
The procedure :
Defeating him has nothing to do with milk. There is no milk to be found anywhere on Super Power island.
Ratman is hiding in the sewer under City Park, with his pet rats and stinging flies.
The display comes when you get your super flying power. To get it, capture the 5 super-villains (Copycat, Speeding Spike, Sir Rebral, Ratman, and Crusher). The pay phone on Main Street will ring as you pass it, and answering it gives you your flying power, so that you can capture Betty Jetty.
Ratman is on Super Power Island. There is a large rat in the sewer entrance to the factory on 24 Carrot Island (climb up into the bypass pipe to elude him).
u spin the weel and a bunch of gunk comes out
Turn the red wheel on top of the last ledge.
There is no such tool (it is a myth perpetuated by cheat sites). The way to capture Ratman is to reach the control wheel at the upper right. Once you are past the rats, turn the wheel to dump sludge on Ratman. Now the flies will leave him and attack you. Avoid them and jump over to cuff Ratman.
The swarm of little black objects around Ratman are stinging flies (not bees). They only attack you at first when you try to capture him. When you reach and turn the red wheel at the upper left, sludge is dumped on them and on Ratman. They will then proceed to attack you. You have to temporarily avoid them, then jump up on the big center pipe and over to Ratman, where you knock him out and cuff him.
There is no jetpack on Super Power Island, as there is on Early Poptropica. The ability to fly is an actual "super power" on the island, and is only acquired by defeating the first five super villains (Copycat, Speeding Spike, Sir Rebral, Ratman, and Crusher), using your wits only. The pay phone will then ring and give you flying power, which you need to catch Betty Jetty. (Super Flying Power works only on this island, but comes in handy on the various ad games, when they are accessed from Super Power Island.)
Both restrooms (boy and girl) lead to the sewer where Ratman is hiding.
When you face ratman and his rats and flies, climb to the red wheel at the upper right, which will dump sludge on Ratman. Jump quickly between the rats. Then avoid his flies to jump over to him and cuff him.
The control wheel in the Sewer Room is similar to the three outside that raise and lower the water levels. Except that this one (at the far upper right, past the rats) dumps sludge on Ratman and scares away the biting flies. You still have to get past them and jump over to where Ratman is, to capture him. (see related question)