Wicked Grims are essentially just stronger Grims. They make use of their long, lashing tongue for an additional attack, but other than that, the same tactics apply.
Grims are agile, frog-like humanoid creatures with generally low health and stun thresholds. They attack quickly, and can be a threat when in groups.
Grims are generally easy enough to deal with as long as you aren't surrounded. Their main attack sees them perform a spinning leap at Kratos, and it'll break your guard if you don't parry it. The timing's a bit awkward because there's a slight delay as the Grim starts spinning in midair, but once you're used to it, Grims don't really have much else to offer.
Grims can also be slippery little buggers if they aren't killed quickly, running away from danger if your combo doesn't rack up enough damage. Your best bet is to launch them with a heavy attack, leaving them completely vulnerable to the next onslaught.
How many Wicked Grims have you smashed into submission? Be sure to check out our full God of War Ragnarok guide for information on how to beat every enemy, and much more.