Spawn Of Scutter had what I think was a low/full pressure (I can't remember but I know they tried to run a low pressure ram at full pressure in series 7 and blew the end cap off the ram when they fired it unloaded) spike pointing upwards in series 4 - it was very good at flipping opponents over, but not very good at all at putting holes in them even with the extra gravitational assistance...

The only other robots I can think of that had *serious* spike weapons were 101 and Pain - 101 kept running into the problem of pushing its opponents away instead of doing damage even on full pressure CO2, and Pain's weapon was banned due to the fact it involved barely controlled explosions and the robot didn't work!

Apologies for hijacking thread, I'll go back to lurking ^^;;