This monster is efficient at destroying multiple monsters and gaining advantage. Just the threat of damage from this monster can discourage your opponent from using LP-intensive cards like "Solemn Warning".
This card has synergy with "Worm Yagan" and "Worm Xex". "Yagan" bounces monsters that "Tentacles" is not able to destroy, and "Xex" mills targets for "Tentacles" to remove, as well as bringing out "Yagan".
On an empty field, Normal Summon "Worm Xex" and use its effect to dump "Worm Yagan", then revive "Yagan" by its own effect. Attack for 1800. Next turn, Normal Summon this card. Activate this card's effect, and flip "Yagan". Attack with all for 1800 + 1000 + 1700 + 1700 = 6200. With the original 1800, this adds up to 8000.
Use two of this monster to attack directly 4 times, then follow up with "Solar Ray" for an OTK.
To make this card even more scary, attack your opponent's monster that has the highest ATK and then use "Honest" so that the next attack with "Worm Tentacles" will still have the ATK gained from "Honest". If possible, make the second attack a direct one.