I've only been playing Splinterlands for a week, so I'm going to talk about my experience with a level 1 Sand Worm. The stats it has at that level are: 1 speed, 5 melee attack 5 health, and the sneak ability. It costs 9 mana and is a Reward card in the Neutral splinter.
This is an excellent card for new players to pick up, although it does fall off in general use quite quickly. It remains strong in reverse speed and extremely high mana battles.
It's a low mana battle with reverse speed. I'm confident my Sand Worm can be a wrecking ball in this situation. I put Torhilo the Frozen in the tank slot and I use Furious Chicken and Albatross behind it in the hope that this will be enough to buy my Sand Worm time. The Sand Worm I put in the final slot with the responsibility to do the vast majority of my meaningful damage.
The good news for me right off of the bat is my opponent is running magic into me, my gamble to try to mitigate magic damage has paid off. My Sand Worm kills my opponent's Spirit Miner, then it kills my opponent's Ancient Lich. At that point the threats have been neutralized. My opponent tried to defend from the front but that sneaky Sand Worm went around my opponent's defences.
The second case study is a battle with high mana and the equalize and enrage rules. My opponent and I both used a Sand Worm here. It wasn't ideal, but mine took out my opponent's healer while my opponent's Sand Worm tried to take out my Kron. This could've gone either way. As it turned out, my Kron ended up just healing through all of this, which negated a lot of what my opponent was trying to do. If Sand Worm wasn't so slow, it would've had a better chance of landing a killing blow on Kron, which is why I love it in reverse speed more than any other mode.
The Sand Worm being slow and missing is the theme here. In this battle I was against a Sand Worm rather than using one myself. It does some early work and things are looking good, but it eventually runs into a problem, it can't hit anything.