Does anyone know an EXACT way to make this thing follow me???? I've tried so many times and read just about every walkthrough! These classic SIerra games have the WORST fan-made walkthroghs I've ever seen! This is what I do: wait until it appears and starts shooting, then I walk into the left cave... it walks right up to the cave, you can see in the imprints, then when it walks under the waterfall it becomes visible shortly, but if I jump across the ledge, I see the imprints moving back away from the caves then it disappears, and I have to walk back over and wait for it to appear again... If I wait on the one ledge before jumping across, it appears in the walkway and shoots me! So to recap, as soon as I jump across the ledge, it walks away from cave and leaves the screen completely.. If I stand on the west ledge and wait, it shoots me... the walkthroughs make it 1000 times worse, with the blatantly incorrect information, e.g. go left, when it should be right, use the hand icon, when it is the walk icon needed, etc etc

When you jump across the ledge, you are supposed to climb the rock, then use the stick to dislodge the rock. The rock will fall through the cave and hit WD40.

I know this question is a year old, but it confused me as well and it appears as the top search result on Google without an explanation of what's going wrong. So maybe we were having the same issue and this will help some future players.

The part that got me was I was expecting WD40 to appear at the cave entrance directly below the boulder. I mean, no way Roger could launch that huge boulder across the gap, right?

Well, as it turns out, that's exactly what he does. So when you see the footprints heading through the water/waterfall, you quickly jump across, climb up to the boulder and use the stick without any delay between any of those steps. He'll launch the boulder across the gap, it'll go into the cave, down the ramp and send WD40 flying.

Hopefully that helps someone out.

I was also stuck because I kept thinking WD40 will either follow Roger up onto the ledge or appear in the hole below the boulder. But no. You are supposed to quickly jump over the gap, climb up to the boulder and dislodge it with the rod. The boulder will skip across the gap, go through the hole you came through a few seconds ago, and "bowl over" WD40. This is a tricky one indeed.