After a decently calm Wednesday that lifted the major averages, Jim Cramer says Thursday's James Comey testimony, U.K. snap elections, and European Central Bank meeting can seem downright perilous to Wall Street's bears.

"The hand-wringers will be out in full force," the "Mad Money" host warned. "I bet the same people who told you to sell the last time [Donald] Trump was in trouble — the ones who think this rally is predicated on total Trump policies — will tell you to sell again. I'm sure the same people who bolted when Brexit occurred already have one foot out the door. I can promise you there are people who will genuinely flip out if the ECB indeed does remove [its] stimulus."