Im new to the competitive battling scene, so am a little confused as to what i should use as my lead. I want something to set up entry hazards, mainly stealth rock, and was thinking of a terrakion, or a deoxys D/S, but what I dont understand is why i should consider running taunt on these pokemon, since a lot of sets recommend taunt for a quick entry setter. If I use a Deoxys S and my opponent uses deoxys D, how would me using taunt first prevent my opponent from setting up? if he uses spikes, he'll end up with 2 or 3 layers of spikes. I guess the general question im trying to ask is, how do I effectively use taunt?