I had a "trap" of sorts, once, for some pcs. Lead lined scroll case, jammed with 30 sheets of Explosive Runes, with a minimum level dispel glyph trap tied to opening the scroll case on the sheets. A Nystul's Aura was also on it to make it appear non-magical. The party received it from a much lower level npc working for the bbeg they had "intimidated" to giving up his boss's secret plans. Knowing the BBEG, they hit the case with a detect magic because they were cocky, instead of the arcane sight they had previously been using. Then they opened the case.
Needless to say, 4 of the six died to the resulting explosion. The only guy with evasion was the one opening the case, which removed his save. One of the survivors was outside standing guard. The other survivor was outside the range of the blast.
The party put more ranks in sense motive after that, and properly checked things magically.
Once they get res'd.