Oingo Boingo has some really sweet bass lines, but I have no idea what it would take to emulate the sound heard on the bass of songs like "Dead Man's Party" and "Weird Science."
You know, that kind of 'watery' sound?
I know it's gotta be some kind of synth pedal, but does anyone else have some better insight?
How many movie soundtracks have they featured on!?!
I am not familiar with any 'conventional' synth pedal that would pull that off. However someone else might chime in who knows about those wiggy synths with special pickups and such!
Elfman's studio during that time was known as "MIDI Hell" because of the insane maze of cables running between dozens of racks and tables of MIDI gear, keyboards, and computers. I doubt if you asked Danny himself today he could tell you what exactly he used on a given track.
However if you post some MP3 or Youtube links of the specific tunes, we can try to suggest some fx to approach the sounds.
The difficulty isn't so much in the tone itself so much as it is the attack and release of the keyboards. Being the 80's there was no attempt to make it sound remotely like an actual bass so it has that very obviously synthy "bouncy" sound. Short of a MIDI setup on your bass (or an actual keyboard synth) I don't see how you could do it.
Oh, and just because I feel like posting cheesy 80's songs, here are the tones in question:
I'm only guessing but I bet if you took a Sansamp VT pedal and added a Boss SYB synth pedal or some envelope filter of choice and dicked around a little bit you could come mighty close.
Ah yes, the elusive Dangerfield tone. Gotta love it. I think if one was to compress and gate the holy bejeepers out of their bass signal, and then use that as the synth trigger source or tone basis, it might be a start.
help - Oingo Boingo sound 
Gotta love it. I think if one was to compress and gate the holy bejeepers out of their bass signal, and then use that as the synth trigger source or tone basis, it might be a start.
