So, by now I've fully returned to #Splinterlands regularly after few months of inactivity. I managed to reach Gold II League using lower leveled monsters than I did before (now, using only Lv2/Lv3 summoners.)
I did play a bunch of battles recently, but most of the Rulesets I encountered in the last two days weren't suited to use the only Opportunity ability monster that I own: Parasitic Growth. I did use him in few battles, and while I could use a battle that showcases his power, I decided to show you a battle that showcases the Opportunity monsters' weakness:
The battle above shows one of the worst cases when Opportunity monsters won't shine: Furious Chicken & Other Filler Monsters. One of the best ways to counter Opportunity ability is to put a Low-Mana monster with the role of being targeted by the Opportunity ability.
While it's still useful to kill these filler monsters, doing so protects the actual monsters that need to be rid off. I love the strategy of this. When you predict that the opponent will use a monster like that, it will change how to use your opportunity ability. Don't you think so?
Answering Carrie Questions:
How do I deal with this? How I protect them for as long as possible?
I think having this ability is a good compromise for being slow and weak. I usually put my Opportunity users in the middle position so that they don't aren't reached by a monster who kills my tank, and they won't be assassinated by a Sneak ability monster.
The weak point of this strategy is when the opponent uses Opportunist with a higher Speed/Health than the one I'm using. I usually blame my luck if this happened.
The slow speed actually makes them very useful in Reverse Speed Ruleset battles. I don't fail to put Parasitic Growth in any battle that has the Ruleset. Though in normal situations, he's likely to die before killing any opponent's monster, especially if the opponent had a Opportunity ability themselves.
The stats of the Lv3 monster I have
While Parasitic Growth is a Neutral monster, I tend to use him mainly with my Fire Splinter teams (using Goblin Mech as a Tank,) because of the extra attack point the summoner Marlic Inferno.
Another Opportunity monster I'm interested in is Serpentine Spy which is better than Parasitic Growth in almost every aspect (except health.) I'll probably buy him from Peakmonsters sometime in the future.